Stomach pain has dozens of possible causes, ranging from something as simple as trapped gas to conditions that need prompt medical attention. The location of your pain, how it started, and what other symptoms you have are the biggest clues to what’s going on. Most episodes come from everyday triggers like food reactions, stress, or mild infections, but understanding the full range of possibilities helps you figure out whether to wait it out or get help.
Where the Pain Is Matters
Your abdomen contains many organs packed closely together, and the location of your discomfort often points directly to the source. Upper right pain is commonly linked to your gallbladder or liver. Upper left pain may come from your stomach itself, your pancreas, or occasionally your heart. Lower right pain is the classic location for appendicitis, while lower left pain often signals issues with the lower colon, like diverticulitis.
Pain that’s hard to pin down to one spot is actually the most common type. Internal organs send pain signals through nerve fibers that are wired differently than your skin. These signals travel to the same part of your spinal cord as signals from your skin and muscles, which is why your brain sometimes misreads where the pain is actually coming from. This is called referred pain, and it’s why a gallbladder problem can make your shoulder ache, or why heart trouble sometimes feels like stomach pain.
Everyday Causes That Are Usually Harmless
Gas and bloating are the most frequent culprits behind stomach discomfort. Swallowing air while eating quickly, drinking carbonated beverages, or eating high-fiber foods can all cause cramping and pressure that feels surprisingly intense. Constipation is another extremely common cause, creating a dull, persistent ache in the lower abdomen that resolves once things start moving again.
Stress and anxiety directly affect your gut. Your digestive tract has its own extensive network of nerves, and emotional distress can trigger cramping, nausea, and changes in bowel habits. This connection works both ways: ongoing gut problems can increase anxiety, and anxiety can worsen gut symptoms. In children especially, stomachaches caused by anxiety or depression are common enough that pediatricians routinely screen for them.
Food Poisoning vs. Food Intolerance
These two get confused constantly, but they work very differently. Food poisoning happens when you eat food contaminated with bacteria or toxins. The onset can be rapid (within hours) or delayed (a day or two later), and a key giveaway is that it strikes even with foods you’ve eaten many times before without problems. Vomiting and diarrhea are the hallmark symptoms. In rare cases, contaminated fish can cause neurological symptoms like tingling or numbness, which food intolerance never does.
Food intolerance, on the other hand, is predictable. It happens because your body can’t properly break down a specific component of food, like lactose in dairy or fructose in certain fruits. The pain tends to show up reliably when you eat that food and typically involves bloating, gas, and cramping rather than vomiting or fever. Unlike food poisoning, intolerance isn’t dangerous, just uncomfortable.
Stomach Lining Problems: Gastritis and Ulcers
Your stomach lining protects itself from its own acid by producing a layer of mucus and bicarbonate. When that protective barrier breaks down, acid starts irritating or eroding the lining, causing gastritis (inflammation) or ulcers (open sores). The most common reasons this barrier fails are infection with a specific bacterium called H. pylori and regular use of anti-inflammatory painkillers like ibuprofen or aspirin.
Smoking also increases the risk significantly, and the more you smoke, the higher the risk. Smokers heal more slowly from ulcers and are more likely to have them return. The pain from gastritis or ulcers typically sits in the upper middle part of your abdomen and often has a burning quality. It may get better or worse after eating, depending on the exact location of the problem.
IBS and Inflammatory Bowel Disease
Irritable bowel syndrome (IBS) is a collection of symptoms, not a disease. It causes cramping, bloating, diarrhea, constipation, or alternating bouts of both. If a doctor examined your colon during an IBS flare, it would look completely normal. There’s no visible inflammation or damage. Symptoms often begin in late adolescence or early adulthood and tend to flare during periods of emotional stress.
Inflammatory bowel disease (IBD), which includes Crohn’s disease and ulcerative colitis, is fundamentally different. IBD causes actual inflammation that damages the intestinal wall and is visible on imaging and during colonoscopy. It can lead to bleeding, anemia, weight loss, and fever, none of which are features of IBS. IBD also carries an increased risk of colon cancer over time. The distinction matters because IBS is managed mainly through diet and stress reduction, while IBD requires medical treatment to control the inflammation and prevent permanent intestinal damage.
Causes That Aren’t Digestive at All
Not all stomach pain comes from your stomach or intestines. Kidney stones can cause severe pain that wraps from your back around to your lower abdomen. Urinary tract infections often produce lower abdominal pressure and discomfort alongside burning during urination.
In women, the pelvic organs are a frequent source of lower abdominal pain. Ovarian cysts, endometriosis, and pelvic inflammatory disease can all produce pain that feels like a digestive problem. An ectopic pregnancy, where a fertilized egg implants outside the uterus, causes lower abdominal pain that can become a medical emergency. In men, testicular torsion (twisting) can refer pain into the lower abdomen. Even pneumonia in the lower lungs can sometimes present as upper abdominal pain, which catches many people off guard.
Stomach Pain in Children
Kids get stomachaches from many of the same things adults do, plus a few causes that are more specific to childhood. Swallowed objects (coins are the classic offender), abdominal migraines, and colic in infants are all common. Children are also more prone to stomach pain from strep throat and mononucleosis, which adults don’t typically associate with abdominal symptoms. Intussusception, where one section of intestine telescopes into another, is a childhood emergency that causes sudden, severe cramping that comes in waves, often with a characteristic currant-jelly stool.
Appendicitis: The Classic Emergency
Appendicitis follows a recognizable pattern. Pain typically starts as a vague ache around the belly button that’s easy to dismiss. Over several hours, nausea and vomiting develop, then the nausea fades and the pain migrates to the lower right abdomen, becoming sharper and more intense. Moving, coughing, sneezing, or taking a deep breath makes it worse. Loss of appetite, fever, bloating, and an inability to pass gas round out the picture.
The most tender spot in a typical case is called McBurney’s point, located about one-third of the way along a line drawn from your right hip bone to your belly button. This progression from vague central pain to sharp right-sided pain over 12 to 24 hours is the pattern worth recognizing, because appendicitis gets more dangerous the longer it goes untreated.
Signs That Need Urgent Attention
Most stomach pain resolves on its own or with simple measures. But certain combinations of symptoms suggest something more serious is happening. Pain so severe that it interferes with your ability to function, walk, or find a comfortable position is one clear signal. Uncontrollable vomiting or inability to keep liquids down is another, because dehydration can escalate quickly.
Being completely unable to have a bowel movement while also experiencing significant bloating and pain raises concern for a bowel obstruction, especially if you’ve had abdominal surgery in the past, since scar tissue can cause the intestine to kink or stick together. Pain that resembles something you’ve experienced before but feels distinctly worse or different this time also warrants attention. Your body’s comparison to its own history is surprisingly reliable information.
How Doctors Figure Out the Cause
When stomach pain doesn’t have an obvious explanation, imaging is the main tool doctors use to look inside. CT scans are the preferred first choice for most adults because they provide a detailed view of the entire abdomen and can identify a wide range of problems, from abscesses to bowel obstructions to kidney stones. Ultrasound is less sensitive for general abdominal pain but is the go-to option during pregnancy, where avoiding radiation matters. For non-pregnant adults, some centers will start with ultrasound and follow up with a CT scan if the results are negative or unclear, which gives the best overall chance of catching the problem.
Blood and stool tests help narrow things down further. Markers of inflammation, infection, or anemia point doctors toward specific diagnoses. For suspected IBS, there’s no single test that confirms it. Instead, doctors diagnose it by ruling out other conditions first, using a combination of blood work, stool samples, and sometimes endoscopy or imaging to make sure nothing else is going on.