Stomach pain has dozens of possible causes, ranging from something as simple as gas or a pulled muscle to serious conditions requiring emergency care. The location, timing, and quality of your pain are the most useful clues for narrowing down what’s going on. Most episodes resolve on their own, but understanding the patterns behind abdominal pain helps you recognize when something needs attention.
Where It Hurts Matters
Your abdomen is divided into four quadrants, and the location of your pain often points toward specific organs. Pain in the upper right side is most commonly linked to gallbladder problems (gallstones or gallbladder inflammation), liver issues, or kidney stones. Upper left pain is more associated with stomach inflammation, peptic ulcers, or pancreas problems. A heart attack can also cause upper left abdominal pain, which is why chest and stomach pain together should always be taken seriously.
Lower right abdominal pain is the classic location for appendicitis, though it also occurs with inflammatory bowel disease, irritable bowel syndrome, and in women, ovarian cysts or ectopic pregnancy. Lower left pain most often signals diverticulitis, especially in adults over 50, or similar gynecological and bowel conditions. Pain that’s hard to pinpoint or seems to move around is common with gas, viral infections, and irritable bowel syndrome.
The Most Common Everyday Causes
For most people searching this question, the culprit is one of a handful of frequent, non-emergency conditions. Gastritis (inflammation of the stomach lining) causes a burning or gnawing pain in the upper abdomen, often worsened by eating. A bacterial infection called H. pylori is one of the leading causes of gastritis and ulcers. Roughly 44% of adults worldwide still carry this infection, though many never develop symptoms. When they do, the result is typically persistent upper abdominal pain, bloating, and nausea. A simple breath test or stool test can detect it, and a course of antibiotics clears it.
Gas and bloating are probably the single most common cause of intermittent stomach pain. Swallowed air, high-fiber foods, lactose intolerance, and carbonated drinks all contribute. The pain can be surprisingly sharp and may shift around the abdomen as gas moves through the intestines. Food poisoning and viral gastroenteritis (“stomach flu”) cause sudden-onset cramping alongside nausea, vomiting, or diarrhea that typically peaks within 24 to 48 hours.
Constipation is an underappreciated cause of abdominal pain, particularly in children and older adults. When stool backs up in the colon, it creates pressure and cramping that can be felt across the lower abdomen or even higher up.
Medications That Damage the Stomach Lining
Anti-inflammatory painkillers like ibuprofen and aspirin are a major and often overlooked cause of stomach pain. These drugs work by blocking enzymes called COX-1 and COX-2, which are involved in inflammation. The problem is that COX-1 also helps maintain the protective mucus lining of your stomach. When you suppress it, the stomach responds with abnormal contractions that disrupt blood flow to the lining, making it vulnerable to acid damage. Your body tries to compensate by ramping up COX-2 to protect the mucosa, but if you’re taking a drug that blocks both enzymes, that backup system fails too.
The result can range from mild irritation to full-blown ulcers and bleeding. Taking these medications with food helps, but regular long-term use still carries significant risk. If you notice stomach pain that coincides with routine use of anti-inflammatory painkillers, that connection is worth paying attention to.
Chronic and Recurring Pain
When stomach pain keeps coming back over weeks or months, a few conditions rise to the top of the list. Irritable bowel syndrome (IBS) affects an estimated 10 to 15% of the population and is diagnosed when you’ve had recurring abdominal pain at least one day per week for three months, with symptoms present for at least six months total. The pain must be connected to bowel movements, a change in how often you go, or a change in stool consistency. IBS doesn’t cause visible damage to the gut, but the discomfort is real and can significantly affect quality of life.
Peppermint oil capsules have some of the strongest evidence for IBS symptom relief. A meta-analysis of clinical trials found that peppermint oil was roughly twice as likely as a placebo to improve both overall IBS symptoms and abdominal pain specifically. It works by relaxing the smooth muscle in the intestinal wall, reducing the spasms that cause cramping.
Inflammatory bowel disease (Crohn’s disease and ulcerative colitis) causes chronic pain along with bloody stools, weight loss, and fatigue. Unlike IBS, these conditions involve actual inflammation and tissue damage visible on imaging or colonoscopy. Peptic ulcers, often driven by H. pylori or long-term painkiller use, cause a burning pain that may improve or worsen with eating depending on the ulcer’s location.
Pain That Isn’t Coming From Your Stomach
Not all pain felt in the belly originates there. This is called referred pain, and it catches many people off guard. A heart attack can present as upper abdominal pain, particularly in women, older adults, and people with diabetes. Pneumonia in the lower lungs sometimes causes upper abdominal pain that mimics a gallbladder attack. Kidney stones frequently cause flank pain that wraps around to the front of the abdomen.
In women, pelvic conditions like endometriosis, ovarian cysts, pelvic inflammatory disease, and ectopic pregnancy can all produce pain that feels like it’s coming from the lower abdomen or stomach. An ectopic pregnancy typically causes one-sided lower abdominal pain along with vaginal bleeding six to eight weeks after the last menstrual period, and it requires immediate medical attention.
Two Types of Abdominal Pain Feel Different
Your body processes abdominal pain through two distinct pathways, which is why stomach pain can feel so different from one episode to the next. Visceral pain comes from the organs themselves. It’s typically dull, crampy, and hard to pinpoint. You might wave your hand over a general area rather than pointing to one spot. This is the kind of pain you feel with gas, early appendicitis, or menstrual cramps.
Somatic pain comes from the abdominal wall or the lining of the abdominal cavity. It’s sharp, well-localized, and tends to get worse with movement or coughing. When appendicitis progresses and the inflammation reaches the abdominal lining, the vague belly ache transforms into a sharp, specific pain in the lower right side. That shift from dull-and-vague to sharp-and-localized often signals that a condition is getting more serious.
Signs That Need Immediate Attention
Most stomach pain doesn’t require a trip to the emergency room, but certain patterns signal something potentially dangerous. Sudden, severe pain that hits like a switch being flipped raises concern for a vascular emergency like a ruptured aneurysm or a perforated organ. Abdominal rigidity, where the muscles of your belly wall stay rock-hard and won’t relax even when you breathe in, suggests the abdominal lining is inflamed or irritated by blood or digestive contents that have leaked where they shouldn’t be.
Vomiting blood or material that looks like coffee grounds points to bleeding in the stomach or esophagus. Severe pain with a distended belly, inability to pass gas, and vomiting suggests a bowel obstruction. Notably, fever is less reliable as a warning sign than most people assume. It’s absent in over 30% of appendicitis cases and in the majority of gallbladder infections. So the absence of fever doesn’t rule out something serious.
Appendicitis deserves special mention because it’s common and follows a recognizable pattern: pain that starts vaguely around the belly button, then migrates over several hours to the lower right side, accompanied by loss of appetite, nausea, and sometimes a low-grade fever. That migration pattern is one of the most distinctive in medicine, and recognizing it can make the difference between a straightforward surgery and a ruptured appendix.