Stomach pain has dozens of possible causes, ranging from something as simple as gas or a pulled muscle to conditions that need urgent medical attention. The location, timing, and type of pain all offer clues about what’s going on. More than 40% of people worldwide meet the criteria for at least one functional gastrointestinal disorder, meaning stomach pain without a clear structural cause is extremely common.
Where the Pain Is Matters
Your abdomen contains many organs packed into a relatively small space, and pain in different areas points to different problems. Upper right pain often involves the liver, gallbladder, or right kidney. Upper left pain is more likely related to the stomach itself, the spleen, or the pancreas. Lower right pain raises concern for the appendix, while lower left pain commonly involves the lower colon, where problems like diverticulitis tend to show up. Pain around or below the navel can involve the bladder, uterus, or small intestine.
Some pain doesn’t stay in one place. Appendicitis classically starts as a vague ache around the belly button, then migrates to the lower right side over several hours. Kidney stones typically begin as flank pain and shift as the stone moves through the urinary tract, sometimes radiating to the groin or testicles. Pain that moves or changes location is worth paying attention to, because it often signals a progressing condition.
Digestive Causes
The most common culprits are digestive in nature. Gas, bloating, constipation, and indigestion account for a huge share of everyday stomach pain and usually resolve on their own. Eating too quickly, swallowing air, or consuming foods your body struggles to break down (dairy if you’re lactose intolerant, for example) can all trigger short-lived discomfort.
Irritable bowel syndrome (IBS) affects roughly 4% of the global population under stricter diagnostic criteria, though older definitions put the number closer to 10%. IBS causes recurring cramping, bloating, and changes in bowel habits without any visible damage to the intestines. It tends to flare with stress, certain foods, or hormonal changes. Functional dyspepsia, a related condition, produces chronic pain or burning in the upper stomach area even when tests come back normal.
Acid reflux and gastroesophageal reflux disease (GERD) cause a burning sensation in the upper abdomen or chest when stomach acid flows back into the esophagus. Peptic ulcers produce a gnawing or burning pain in the middle upper abdomen that often worsens between meals or at night, when the stomach is empty. Gastroenteritis, the “stomach bug,” brings on sudden cramping along with nausea, vomiting, or diarrhea, and typically runs its course in one to three days.
Gallbladder and Pancreas Problems
Gallbladder inflammation, or cholecystitis, causes persistent pain in the upper right abdomen or just below the breastbone. It often comes on after a fatty meal and may be accompanied by nausea, vomiting, and fever. Gallstones are the usual trigger. The pain tends to be steady rather than crampy and can last for hours, which distinguishes it from the brief twinges of gas or indigestion.
Pancreatitis produces intense upper abdominal pain that frequently radiates to the back. It can be caused by gallstones, heavy alcohol use, or certain medications. The pain often feels worse after eating and when lying flat, and it may improve slightly when leaning forward.
Medications That Irritate the Stomach
Common over-the-counter pain relievers like ibuprofen, aspirin, and naproxen are among the most frequent medication-related causes of stomach pain. These drugs reduce the stomach lining’s ability to protect itself from acid, leading to irritation, reflux, and in some cases ulcers or bleeding. The concerning part is that serious gastrointestinal damage from these medications can happen at any point during use and without warning symptoms. Taking them with food or using the lowest effective dose helps reduce risk, but doesn’t eliminate it.
Antibiotics commonly cause stomach cramps, nausea, and diarrhea by disrupting the balance of bacteria in your gut. Iron supplements are another well-known offender, often producing nausea, cramping, and constipation.
Causes Outside the Digestive System
Not all stomach pain originates in the stomach or intestines. Kidney stones and kidney infections cause pain that can feel like it’s coming from the abdomen, especially in the flanks or lower belly. Bladder infections produce lower abdominal pressure and pain along with burning during urination. In women, ovarian cysts, endometriosis, and ectopic pregnancy can all cause significant abdominal pain. An ectopic pregnancy may start as a dull ache and progress to sharp, stabbing pain, becoming an emergency if a fallopian tube ruptures.
Pulled or strained abdominal muscles from exercise, coughing, or heavy lifting can mimic internal pain. The giveaway is that muscle pain usually worsens with movement, twisting, or tensing your core, while organ-related pain doesn’t follow those patterns as predictably. Occasionally, pain from the chest or pelvis gets “referred” to the abdomen. Heart attacks, pneumonia, and blood clots in the lungs can all produce upper abdominal pain that mimics a digestive problem, which is one reason sudden, severe stomach pain paired with shortness of breath deserves immediate attention.
Stress and the Gut-Brain Connection
Stress, anxiety, and emotional distress have a direct line to your gut. The digestive system has its own extensive network of nerves, and psychological stress can speed up or slow down digestion, increase acid production, and heighten your sensitivity to normal digestive sensations. This is one reason IBS and functional dyspepsia flare during stressful periods. The pain is real, not imagined, even when no structural damage is present.
Signs That Need Urgent Attention
Most stomach pain is temporary and benign, but certain features signal something more serious. Abrupt, excruciating pain can indicate a ruptured organ, a blocked blood vessel supplying the intestines, a kidney stone lodged in a duct, or a tear in the aorta. Pain that gets dramatically worse when you release pressure on the abdomen (rebound tenderness), involuntary tightening of the abdominal muscles, or pain triggered by coughing or tapping your heel on the ground all suggest inflammation of the abdominal lining.
Vomiting blood, passing bloody or black stools, blood in urine, or having no bowel sounds at all are additional warning signs. Abdominal pain combined with shortness of breath, chest pain, or symptoms that worsen with physical activity may point to a cardiac or pulmonary cause rather than a digestive one. High fever alongside abdominal pain raises concern for infection or abscess.
How Stomach Pain Gets Diagnosed
When pain is diffuse or hard to pin down, a CT scan of the abdomen and pelvis with contrast dye is the go-to imaging study. It can screen for a wide range of problems, from appendicitis to bowel obstruction to kidney stones. Ultrasound is less sensitive for general abdominal pain but works well for specific concerns like gallstones, and it’s the preferred first step during pregnancy because it avoids radiation. For pregnant patients with unclear ultrasound results, MRI provides a radiation-free alternative.
Many cases of stomach pain don’t require imaging at all. A doctor can often narrow the diagnosis through your description of the pain, its timing, associated symptoms, and a physical exam. Blood and urine tests may be added to check for infection, inflammation, or organ function problems. If symptoms are chronic and recurrent, an upper endoscopy or colonoscopy may be recommended to look directly at the lining of your digestive tract.