A cramp in your side is usually your body reacting to something ordinary, like running soon after a drink, gas caught in a bend of the bowel, or a tight muscle between the ribs. But the side of the belly sits over many organs, including the bowel, the kidneys and, in women, the ovaries and tubes, so the same feeling can occasionally come from something that needs treatment. The useful clues are less the cramp itself and more what came with it: whether it started during exercise, how fast it fades, and whether fever, vomiting or blood join in.
The Exercise Stitch
A stitch is a sharp or cramping pain on one side of the belly that comes on during exercise, often in the upper side just under the ribs. It may come from irritation of the thin lining that coats the inside of the belly wall and the underside of the diaphragm.1PubMed Central. Exercise-Related Transient Abdominal Pain (ETAP) The pain is worse with movement, and because that lining shares nerves with the shoulder, it can sometimes be felt at the tip of the shoulder.2PubMed Central. Exercise-Related Transient Abdominal Pain (ETAP)
A full stomach may add to it. Drinking a large amount before running brought on stitches, possibly as the heavy gut tugs on the ligaments that hold it in place.3PubMed. Investigation of the side pain “stitch” induced by running after fluid ingestion Children get stitches more often than adults, possibly because their belly lining is larger relative to their body.4PubMed Central. Exercise-Related Transient Abdominal Pain (ETAP) Other things raise your chances: activities with repeated up-and-down torso movement such as running and horse riding, and being new to a sport or pushing harder than usual. Either way, a stitch typically eases quickly once you stop the activity.5PubMed Central. Exercise-Related Transient Abdominal Pain (ETAP)
A stitch sits on one side and you can usually pinpoint it with a finger. It is often worse with jolting moves like running or riding. Pain that returns at rest or lasts for hours is not a stitch.
Stitches tend to become less frequent as you train regularly, though the exact reason isn’t settled.
If pain during exercise is crushing, spreads to the arm or jaw, or comes with breathlessness out of proportion to the effort, stop and get urgent help.
How to Stop a Stitch and Prevent the Next One
Start by slowing your pace or walking for a bit.6Herzog Medical. How do you prevent a stitch when running? Then take deep breaths in and slow breaths out, with your hands on your hips if that helps.7Herzog Medical. How do you prevent a stitch when running? Some runners take 3 to 5 deep breaths with sharp exhales, then breathe in for three steps and out for two.8ASICS. How to Prevent and Stop Exercise-Related Transient Abdominal Pain (ETAP): The Runner’s Guide to Stitches Landing on the opposite foot as you exhale can move the load away from the sore side. Give the pattern several breaths before you give up on it, since relief often isn’t instant.
You can also press two or three fingers into the sore spot, pushing in and slightly up as you breathe out, for a few breaths.9ASICS. How to Prevent and Stop Exercise-Related Transient Abdominal Pain (ETAP): The Runner’s Guide to Stitches Or stop and stretch: raise your arms overhead and bend gently to each side, then forward.10ASICS. How to Prevent and Stop Exercise-Related Transient Abdominal Pain (ETAP): The Runner’s Guide to Stitches Once the pain has gone, build your pace back up gradually.11ASICS. How to Prevent and Stop Exercise-Related Transient Abdominal Pain (ETAP): The Runner’s Guide to Stitches
Sip smaller amounts instead of drinking a lot at once. Leave a gap of a couple of hours between a big meal and hard exercise. Warming up gradually lets your breathing settle before you go hard. Stronger core muscles may help, though the evidence is limited.
A stitch is different from a true muscle cramp, where a muscle locks tight, often in the calf or thigh and not usually at the side of the belly. Muscle cramps are linked to sweat loss and salt balance, and salty sports drinks may lower the risk.12PubMed Central. Muscle Cramping During Exercise: Causes, Solutions, and Questions Remaining
Muscle and Rib Causes
The small muscles between the ribs can be strained by twisting, lifting, coughing hard or sport, leaving the area tender to touch.13PubMed. Musculoskeletal problems of the chest wall in athletes Pain from the upper back can also spread round to the side of the chest.14PubMed. Musculoskeletal problems of the chest wall in athletes
In slipping rib syndrome, one of the lower ribs is loose enough to slip or click under the rib above.15PubMed. Slipping Rib Syndrome: A review of evaluation, diagnosis and treatment It pinches the nerve running under that rib, causing pain in the lower ribs or upper belly.16PubMed. Slipping Rib Syndrome: A review of evaluation, diagnosis and treatment The pain often comes on suddenly with a jerking or twisting movement.17PubMed Central. A Comprehensive Review of Slipping Rib Syndrome: Treatment and Management Slipping rib is often missed, so pain there that persists despite painkillers is worth raising with a doctor.18PubMed. Slipping Rib Syndrome: A review of evaluation, diagnosis and treatment19PubMed. Slipping Rib Syndrome: An elusive diagnosis
Pain that worsens with twisting, deep breaths or reaching, and that started after a specific movement or effort, points toward muscle or rib. A click or pop felt at the lower ribs points toward slipping rib.
To check, use a fingertip to press gently along the ribs and the gaps between them where it hurts. If pressing recreates your exact pain, a muscle or rib cause is more likely, but that is one clue and not proof. Pain that is deep, doesn’t change with pressure or movement, or comes with fever or vomiting points elsewhere.
For a strain, rest from the movement that hurts for a few days. Use ice early, then gentle heat, and take over-the-counter pain relief while it heals. If it isn’t improving after a week or two, see a doctor.
Gas, Bowel Problems, Appendicitis and Diverticulitis
The large bowel bends sharply under each side of the rib cage, and gas and stool can get trapped at these bends.20IBS Dietitian. IBS Rib Pain: Why It Happens and How to Manage It The pressure can feel just like rib or side pain.21IBS Dietitian. IBS Rib Pain: Why It Happens and How to Manage It In people with irritable bowel syndrome, foods like wheat and onions make the same gas as in others but are felt as more painful, because the brain responds more strongly.22PubMed. Gut-brain axis dysfunction underlies FODMAP-induced symptom generation in irritable bowel syndrome
Gas pain shifts around, comes in waves, and eases after passing wind or a bowel movement. Bloating and rumbling often go with it. Pain that settles in one spot and steadily worsens over hours is not typical gas.
Appendicitis often begins as a vague ache around the belly button.23JAMA. Diagnosis and Management of Acute Appendicitis in Adults: A Review It then moves to the lower right side as the inflamed appendix irritates the belly lining.24JAMA. Diagnosis and Management of Acute Appendicitis in Adults: A Review That moving pain, fever, or pain when you lift your right leg against resistance make appendicitis more likely.25JAMA. Does This Patient Have Appendicitis? Vomiting that started before the pain makes it less likely.26JAMA. Does This Patient Have Appendicitis?
Walking, coughing or going over a bump in the car often makes it sharply worse, so people tend to lie still. Loss of appetite is common, and so is mild nausea once the pain starts. Not everyone follows the classic pattern, so pain that keeps worsening should be seen even if it never moved to the lower right.
If you suspect appendicitis, don’t wait for the pain to settle in the right place before getting help, because the pattern isn’t reliable. Sudden relief followed by worse pain, or a swollen, hard belly, can mean the appendix has burst, which is an emergency.
Diverticulitis is infection or inflammation of small pouches in the bowel wall, and in Western countries it most often affects the lower left side.27PubMed. Emergency medicine updates: Acute diverticulitis Pain and tenderness low on the left are its most common signs.28PubMed. Emergency medicine updates: Acute diverticulitis It is more common after middle age and can bring fever, changed bowel habits and nausea. It needs a doctor, who may give antibiotics or order tests.
Kidney Stones and Kidney Infection
A kidney stone is a small hard lump that forms in the kidney.29PubMed Central. Urolithiasis presenting as right flank pain: a case report When it moves into the tube to the bladder and blocks it, it causes severe cramping spasms.30Ultrasonography. Ultrasonography of acute flank pain: a focus on renal stones and acute pyelonephritis The pain can sit in the side, low back, lower belly or groin.31PubMed Central. Urolithiasis presenting as right flank pain: a case report Many stones pass naturally with pain relief at home after a doctor confirms them.32PubMed Central. Urolithiasis presenting as right flank pain: a case report
A stone attack comes in waves that can make it hard to sit still, and the pain may travel from the side down toward the groin. Nausea and blood in the urine are common. Drinking plenty of water helps prevent new stones.
Stone pain usually doesn’t ease with any position, which is why people with a stone often pace or writhe, whereas muscle pain usually changes with movement or pressure. Pain high in the back below the ribs, to one side of the spine, fits the kidney more than a strained muscle.
Fever, side pain, and burning when peeing together often point to a kidney infection.33PubMed. Renal infarction versus pyelonephritis in a woman presenting with fever and flank pain That combination needs a doctor the same day. These infections usually need antibiotics, and untreated they can spread to the blood. Shivering, vomiting and feeling very unwell are reasons for urgent care.
Ectopic Pregnancy and Other Causes in Women
An ectopic pregnancy grows outside the womb, usually in a fallopian tube. It can cause belly pain low down on one side that comes on suddenly or gradually and may come and go.34nhs.uk. Ectopic pregnancy – Symptoms It ranges from no symptoms at all to a burst tube with heavy internal bleeding.35PubMed Central. The Diagnosis and Treatment of Ectopic Pregnancy So anyone who could be pregnant and has one-sided low pain should take a test and seek same-day care.
One-sided low pain with a late or unusual period is a further reason to consider it, even with contraception. Light vaginal bleeding or spotting, often darker than a normal period, can come with the pain. A positive home test with one-sided pain means a same-day check to find where the pregnancy is, not waiting for it to pass.
A burst tube shows itself through sudden sharp pain that keeps getting worse, feeling faint, dizzy or very pale, and pain at the tip of the shoulder. These need an emergency call, not a wait.
Other causes are milder. Ovulation can cause a brief one-sided twinge mid-cycle. An ovarian cyst can cause aching, while a twisted ovary causes sudden severe pain. Period cramps are usually central and lower.
When to Worry and Go to the ER
Go to emergency care for any of these:
- Pain so severe you can’t move, eat or drink36Mass General Brigham. Abdominal Pain: ER or Urgent Care?
- Pain that came on suddenly37Mass General Brigham. Abdominal Pain: ER or Urgent Care?
- High fever38Mass General Brigham. Abdominal Pain: ER or Urgent Care?
- Blood in stool or vomit39Mass General Brigham. Abdominal Pain: ER or Urgent Care?
- Pain after a fall, crash or blow to the belly40Mass General Brigham. Abdominal Pain: ER or Urgent Care?
A rigid, hard belly that hurts to touch or when the car goes over a bump is a sign of irritation of the belly lining and needs urgent assessment. Feeling faint, pale or very drowsy with pain suggests bleeding or serious infection. Side pain can also occasionally come from the lungs, as with pneumonia, so cough and breathlessness are also reasons to be seen.
Waiting and watching is fine for pain that started with exercise and faded on stopping, gas pain that eases after passing wind, or mild tenderness after a strain that slowly improves. See a doctor if mild pain lasts more than a few days or keeps coming back.
What Happens at the Doctor
Your doctor will ask where the pain started, what it feels like, and what came with it, then press on your belly. They press on different areas to find where it is tender and whether the belly is soft or rigid. Pain that is worse when pressure is suddenly released can point to irritation of the belly lining. They may also press on the back over the kidneys to check for tenderness there.
A urine test checks for blood or infection and a blood test for inflammation.41PubMed. Guidelines of diagnostics and treatment of acute left-sided colonic diverticulitis42PubMed. Emergency ultrasound and urinalysis in the evaluation of flank pain A CT scan without dye finds nearly all kidney stones and reveals a cause outside the kidneys in about one in three people with sudden side pain.43PubMed. Modern approach of diagnosis and management of acute flank pain: review of all imaging modalities Ultrasound avoids radiation and performs about as well as CT for many other causes, so it is often used first, especially in pregnancy.44PubMed. Acute flank pain: comparison of unenhanced helical CT and ultrasonography in detecting causes other than ureterolithiasis
To prepare, note when the pain began and how it has changed, along with fever, vomiting, and any bowel or urine changes. Mention any chance of pregnancy and the medicines you take. If surgery might be possible, avoid eating until you’ve been seen.