Stomach pain can mean dozens of different things, from something as simple as gas or a meal that didn’t agree with you to a condition that needs medical attention. The location of the pain, how it feels, when it started, and what makes it better or worse are the biggest clues to what’s going on. Most episodes are short-lived and harmless, but certain patterns point to specific organs or conditions worth knowing about.
Why Location Matters
Your abdomen contains many organs packed into a relatively small space, and where you feel pain often points directly to which one is involved. Doctors divide the abdomen into four quadrants plus a central upper zone to narrow things down quickly.
Pain in the upper right side sits near your liver, gallbladder, and the first part of your small intestine. Upper left pain is closer to your stomach and spleen. Lower right pain is where your appendix lives, along with part of your colon. Lower left pain often involves the descending colon, where small pouches can form and become inflamed (a condition called diverticulitis). And pain right in the center of your upper abdomen, just below your breastbone, typically involves the stomach itself, the pancreas, or the esophagus.
Pain doesn’t always stay neatly in one spot. It can start in one area and move, or it can radiate outward. Gallbladder pain, for example, often spreads to the right shoulder or back. Knowing where it began and where it traveled helps distinguish one cause from another.
Upper Stomach Pain
The most common reasons for pain in the upper middle abdomen are acid reflux, gastritis (irritation of the stomach lining), and peptic ulcers. These conditions share a burning or gnawing quality. Ulcer pain specifically tends to come in episodes, often worsens at night, and sometimes improves temporarily after eating. Between 75 and 95 percent of ulcers in the upper small intestine are linked to a bacterial infection called H. pylori, though many people don’t know they carry it. Heavy use of anti-inflammatory painkillers like ibuprofen or naproxen is the other major cause.
Pain under the right ribcage after a fatty meal is a hallmark of gallbladder trouble. When a gallstone temporarily blocks the duct that drains bile, the result is intense, squeezing pain that builds to a peak and then gradually fades over 20 minutes to a few hours. It doesn’t come and go in waves during an episode. Instead it holds steady, often severe enough to send people to the emergency room. Eating a large or greasy meal is a common trigger because fat in your food signals your gallbladder to squeeze and release bile.
Pancreatitis, inflammation of the pancreas, causes deep upper abdominal pain that often bores straight through to the back. It tends to come on suddenly and can be severe.
Lower Stomach Pain
Sharp pain in the lower right abdomen that worsens over several hours is the classic presentation of appendicitis. It often starts as a vague ache around the belly button before migrating to the lower right. This is one of the more time-sensitive causes of abdominal pain, since a burst appendix can cause a serious infection.
Lower left pain in adults over 40 is frequently related to diverticulitis. Small pouches that form in the colon wall, most commonly on the lower left side, can trap bacteria and become inflamed or infected. The pain is usually steady and may come with fever or changes in bowel habits.
For women, lower abdominal pain on either side can involve the ovaries or fallopian tubes. Ovarian cysts can cause a sudden, sharp pain if they rupture, though the blood loss is usually minimal. Endometriosis, where tissue similar to the uterine lining grows outside the uterus, causes recurring pain that often worsens around menstruation. An ectopic pregnancy, where a fertilized egg implants in a fallopian tube instead of the uterus, produces localized pain that can become widespread and dangerous if the tube ruptures. Dizziness, fainting, or drops in blood pressure alongside pelvic pain and a missed period are warning signs of this.
Pain Triggered by Eating
If your stomach hurts reliably after meals, the culprit is often something in your diet. Food intolerances and food allergies work through completely different mechanisms, and telling them apart matters.
A food allergy involves your immune system. Even tiny amounts of the trigger food can cause symptoms that range from mild to life-threatening. A food intolerance, on the other hand, happens when your body lacks an enzyme needed to digest a particular food. Lactose intolerance is the most common example. With an intolerance, you can often eat small amounts without any problem, and symptoms (bloating, cramping, diarrhea) show up mainly when you exceed your personal threshold.
Celiac disease falls somewhere in between. It’s an immune reaction to gluten, a protein in wheat and related grains, but it primarily damages the lining of the small intestine rather than triggering the acute allergic responses you’d see with a true food allergy. Over time it can cause chronic pain, bloating, weight loss, and nutrient deficiencies.
Recurring Pain That Won’t Go Away
When stomach pain keeps coming back for months without a clear structural cause, irritable bowel syndrome (IBS) is one of the most common explanations. The formal diagnostic threshold is recurrent abdominal pain at least one day per week for three months, with symptoms that first appeared at least six months before diagnosis. IBS pain is closely tied to bowel movements: it typically gets better or worse with them, and it often comes alongside changes in stool frequency or consistency.
IBS doesn’t damage your intestines or show up on imaging. It’s a disorder of how the gut and brain communicate, which is why stress, anxiety, and poor sleep can make flares significantly worse. That doesn’t make the pain any less real. It just means the usual tests come back normal, which can be frustrating.
When Stomach Pain Isn’t From Your Stomach
One of the trickier aspects of abdominal pain is that it sometimes originates from organs outside the abdomen entirely. A heart attack can present as upper abdominal pain, nausea, or what feels like severe heartburn, especially in women. If upper stomach pain comes with pressure or tightness in your chest, shortness of breath, cold sweats, or sudden dizziness, that combination needs immediate evaluation.
Pneumonia in the lower lobes of the lungs can also cause upper abdominal pain. So can diabetic emergencies, which sometimes produce nausea and belly pain as early symptoms. The point isn’t to make you anxious about every stomachache. It’s that pain in the abdomen plus symptoms that seem unrelated to digestion (chest pressure, difficulty breathing, confusion, fainting) is a combination worth taking seriously.
Signs That Need Urgent Attention
Most stomach pain resolves on its own or with basic care. But sudden, severe abdominal pain that comes on without warning is a category of its own, sometimes called an “acute abdomen.” It often signals something that requires emergency treatment. A few specific warning signs to watch for:
- Rigid, swollen abdomen that’s painful to touch, which can indicate inflammation spreading inside the abdominal cavity
- Pain that worsens with any movement, even gentle pressure or bumping into something, suggesting the lining of the abdomen is inflamed
- Vomiting blood or passing black, tarry stool, which points to bleeding somewhere in the digestive tract
- High fever with abdominal pain, which raises concern for infection or abscess
- Fainting or dizziness with abdominal pain, which can mean internal bleeding or a cardiovascular event
How Doctors Figure Out the Cause
When stomach pain needs investigation beyond a physical exam and basic blood work, imaging is the next step. For most non-pregnant adults with abdominal pain that isn’t clearly localized, a CT scan with contrast is the standard first choice. It picks up a wide range of problems, from infections and abscesses to bowel obstructions and tumors, with sensitivity around 88 percent for detecting abscesses compared to about 75 percent for ultrasound.
Ultrasound is the go-to for pregnant patients and is also the preferred first test when gallbladder disease is suspected, since it’s excellent at detecting gallstones without radiation exposure. For everyone else, some imaging strategies start with ultrasound and move to CT if results are unclear, which offers the best overall sensitivity.
The pattern of your pain matters more than any single test. A doctor will ask when it started, whether it’s constant or comes and goes, what makes it worse, whether it’s related to eating or bowel movements, and whether you have any other symptoms. Those details, combined with where exactly it hurts, often narrow the possibilities before any imaging is ordered.