Pain on the right side of your lower stomach has a wide range of possible causes, from a pulled muscle to appendicitis. The right lower abdomen contains the appendix, the last section of the small intestine, the first part of the large intestine, the right ureter, and (in women) the right ovary and fallopian tube. Any of these structures can produce pain when inflamed, blocked, or injured.
What’s causing your pain depends on how it started, how intense it is, and what other symptoms come with it. Here’s what each possibility looks like and how to tell them apart.
Appendicitis: The Most Urgent Possibility
Appendicitis is the first thing most people worry about, and for good reason. It’s a common surgical emergency, most frequent in people in their teens through their thirties, and it requires prompt treatment. The classic pattern starts as a dull ache around the belly button, then migrates over several hours to the lower right side, settling near a spot roughly one-third of the way between your hip bone and your navel. The pain typically gets sharper and more constant over time rather than coming and going.
Other signs that point toward appendicitis include loss of appetite, nausea or vomiting that starts after the pain begins, a low-grade fever, an inability to pass gas, and pain that gets noticeably worse when you cough, walk, or make jarring movements. If pressing on the left side of your lower abdomen causes a spike of pain on the right side, that’s another strong indicator. The same goes for pain that worsens when you extend your right hip backward while lying on your left side.
Not everyone follows the textbook pattern. The pain can start in the lower right side without the belly-button phase, and some people have a dull persistent ache rather than sharp stabbing pain. If you suspect appendicitis, this is one situation where waiting it out is risky. A ruptured appendix can lead to a serious abdominal infection.
Digestive Causes
The lower right abdomen is home to the ileum, the final section of the small intestine, and the cecum, where the large intestine begins. Several digestive conditions target this area specifically.
Crohn’s disease most commonly affects the end of the small intestine, which sits in the right lower quadrant. It causes chronic or recurring bouts of pain, often with diarrhea, weight loss, and fatigue. Unlike appendicitis, Crohn’s pain tends to develop gradually over weeks or months rather than hours. Flares may coincide with certain foods or periods of stress.
Irritable bowel syndrome can produce cramping pain anywhere in the abdomen, including the lower right side. The pain usually improves or worsens with bowel movements and comes alongside bloating, gas, or alternating constipation and diarrhea. IBS pain tends to be crampy rather than sharp and doesn’t wake you from sleep.
Diverticulitis, while more commonly associated with the lower left side, can occasionally affect the right colon. Colitis, or inflammation of the colon lining, can also produce right-sided pain depending on which segment is involved.
Kidney Stones
A stone that forms in the right kidney may not cause any symptoms at all while it stays put. The trouble starts when it moves into the ureter, the narrow tube connecting the kidney to the bladder. That’s when you get sudden, intense pain in the side and back below the ribs that radiates down toward the lower stomach and groin. The pain comes in waves, surging and easing in cycles that can last minutes to hours.
Kidney stone pain is distinct from most other causes on this list because of its intensity and its restless quality. People with kidney stones typically can’t find a comfortable position, pacing or shifting constantly. You may also notice blood in your urine (sometimes visible, sometimes only detectable on a test), a burning sensation when urinating, or urine that looks cloudy or smells different than usual. Nausea and vomiting are common.
Causes Specific to Women
The right ovary and fallopian tube sit in the lower right abdomen, so several reproductive conditions show up as pain on that side.
Ovarian cysts are fluid-filled sacs that develop on the ovary. Most are harmless and resolve on their own within a few menstrual cycles, but a large or ruptured cyst can cause sudden, sharp pain on one side. A more dangerous situation is ovarian torsion, where the ovary twists on its supporting tissue, cutting off blood flow. Torsion causes severe, sudden pain often accompanied by nausea and vomiting, and it requires emergency treatment.
Ectopic pregnancy occurs when a fertilized egg implants outside the uterus, usually in a fallopian tube. It causes one-sided lower abdominal pain that may start mild and worsen over days. If you could be pregnant and have right-sided pain, especially with vaginal bleeding or dizziness, this needs immediate evaluation. A ruptured ectopic pregnancy can cause life-threatening internal bleeding.
Endometriosis, a condition where tissue similar to the uterine lining grows outside the uterus, often affects the ovaries, fallopian tubes, and pelvic lining. The pain tends to be worst around menstrual periods and is often described as significantly more intense than normal period cramps. Pain during sex and pain with bowel movements or urination, particularly around your period, are common patterns. Pelvic inflammatory disease, an infection of the reproductive organs usually caused by sexually transmitted bacteria, can also produce right-sided lower abdominal pain along with fever, unusual discharge, and pain during sex.
Causes More Common in Men
Inguinal hernias are 8 to 10 times more common in men than in women. They happen when a portion of intestine or abdominal lining pushes through a weak spot in the abdominal wall near the inguinal canal, the passage that carries the spermatic cord into the scrotum. You might notice a visible bulge in the groin area that becomes more prominent when you stand, cough, or strain. The pain often worsens with lifting or prolonged standing and improves when you lie down.
Large inguinal hernias can extend into the scrotum, causing swelling and pain in the testicle. If the trapped tissue loses its blood supply (a strangulated hernia), the pain becomes severe and constant, and the area may feel warm and tender. That situation requires emergency surgery.
Muscle Strain
Not every right-sided pain comes from an organ. A pulled or strained muscle in the abdominal wall is surprisingly common and can mimic internal problems. This typically happens after heavy lifting, intense exercise, or sudden twisting. The pain worsens when you tense your core, like when sitting up from lying down, and you can often pinpoint the exact sore spot with a finger. There’s usually no fever, nausea, or change in bowel habits, which helps distinguish it from deeper causes.
How Doctors Figure Out the Cause
When you’re evaluated for right lower abdominal pain, the process usually starts with a physical exam and questions about when the pain started, whether it’s constant or comes and goes, and what makes it better or worse. Blood work and a urine test help narrow the possibilities.
Ultrasound is typically the first imaging step, especially for women (to evaluate the ovaries and fallopian tubes) and for younger patients with suspected appendicitis. If ultrasound results are unclear, a CT scan provides a more detailed picture. This staged approach, ultrasound first followed by CT if needed, has become standard practice because it gives accurate answers while minimizing unnecessary radiation exposure.
Signs That Need Immediate Attention
Some combinations of symptoms signal that you should get to an emergency room rather than waiting for a regular appointment:
- Pain so severe it interrupts your ability to function
- Vomiting you can’t control or inability to keep liquids down
- Complete inability to have a bowel movement or pass gas along with worsening pain
- Fever with escalating abdominal pain
- Abdominal rigidity, where your stomach muscles feel board-stiff and tense involuntarily
- Dizziness, lightheadedness, or fainting
- Possible pregnancy combined with one-sided pain or vaginal bleeding
If you’ve had abdominal surgery in the past and your current pain feels similar to a previous episode but more severe, that also warrants an ER visit. Scar tissue from prior surgery can cause bowel obstructions, which need urgent treatment.
Mild, intermittent right-sided pain that comes and goes over weeks without fever, vomiting, or weight loss is less likely to be an emergency. But persistent or worsening pain, even at a low level, is worth getting evaluated. Many of the conditions on this list are far easier to treat when caught early.