Pain in the lower right abdomen has several possible causes, ranging from a pulled muscle to appendicitis to a kidney stone working its way down. The most common concern, and the one doctors evaluate first, is appendicitis, but the actual cause depends on the type of pain, how it started, and what other symptoms come with it.
Appendicitis
Appendicitis is the first thing doctors rule out when someone comes in with lower right abdominal pain, and for good reason: it’s the most common surgical emergency involving the abdomen. The appendix is a small, finger-shaped pouch attached to the large intestine in the lower right side.
The pain typically starts as a vague ache around the belly button, then migrates to a specific spot in the lower right abdomen over 12 to 24 hours. That spot, called McBurney point, sits roughly a third of the way between your hip bone and your navel. Pressing on it and then quickly releasing causes a sharp spike of pain, which is one of the hallmark signs doctors check for. The pain usually gets worse with movement, coughing, or sneezing. Nausea, vomiting, low-grade fever, and loss of appetite often follow.
Surgery to remove the appendix remains the standard treatment for both uncomplicated and complicated cases. Current guidelines from the Society of American Gastrointestinal and Endoscopic Surgeons recommend surgical removal, though the operation doesn’t always need to happen within the first few hours. For uncomplicated appendicitis, outcomes are similar whether surgery happens immediately or is delayed beyond 12 hours. In some complicated cases, particularly when there’s a well-formed abscess or significant inflammation, doctors may start with antibiotics and schedule surgery later.
Kidney and Ureteral Stones
A stone that forms in the right kidney and drops into the ureter (the tube connecting the kidney to the bladder) can cause intense lower right abdominal pain. This pain is distinctive: it comes in waves, often described as the worst pain someone has ever felt, and it radiates from the back or side down into the lower belly and sometimes into the groin.
Unlike appendicitis, stone pain rarely holds still. People with kidney stones often can’t find a comfortable position and tend to pace or shift constantly. Urinary symptoms help distinguish this from other causes. You may feel a burning sensation when urinating, notice blood in your urine (pink, red, or brown discoloration), feel an urgent need to urinate frequently, or pass only small amounts each time.
Ovarian Cysts and Gynecological Causes
In women, the right ovary sits in the lower right pelvis, making ovarian problems a common source of pain in this area. Ovarian cysts are fluid-filled sacs that form during the menstrual cycle. Most resolve on their own without symptoms, but when a cyst ruptures or twists the ovary (a condition called ovarian torsion), the pain can be sudden and severe.
Ruptured cysts typically cause a sharp, one-sided pain that begins abruptly, sometimes during physical activity or sex. The pain often improves over hours to days. Ovarian torsion, by contrast, causes pain that doesn’t let up and frequently comes with nausea and vomiting. Torsion is a surgical emergency because the twisted blood supply can permanently damage the ovary.
Ectopic Pregnancy
An ectopic pregnancy, where a fertilized egg implants outside the uterus (usually in a fallopian tube), causes lower abdominal pain on one side along with light vaginal bleeding. Early on, you may have typical pregnancy signs like a missed period, breast tenderness, and nausea. A pregnancy test will come back positive.
The warning signs that distinguish this from a normal early pregnancy are pelvic pain paired with vaginal bleeding. If the fallopian tube ruptures, more unusual symptoms can appear: shoulder pain or a sudden urge to have a bowel movement, caused by blood irritating nerves in the abdomen. Extreme lightheadedness, fainting, or signs of shock signal a rupture, which is a life-threatening emergency.
Inguinal Hernia
An inguinal hernia occurs when tissue, usually a loop of intestine, pushes through a weak spot in the abdominal wall near the groin. It produces a visible or palpable bulge near the pubic bone that may extend into the scrotum or labia. The bulge often becomes more obvious when you cough, strain, or stand up, and may disappear when you lie down.
The pain feels more like pressure, heaviness, or a burning sensation rather than the sharp, acute pain of appendicitis. It tends to worsen with lifting, bending over, or prolonged standing. Some hernias produce a burning or pinching feeling that radiates through the pelvis or down the leg. Not all hernias are visible, though. Indirect inguinal hernias can be tucked behind muscle fibers and not felt on the surface, which is why doctors may ask you to cough or bear down during an exam to make the hernia emerge.
Inflammatory Bowel Disease
Crohn’s disease most commonly affects the terminal ileum, the last section of the small intestine, which sits in the lower right abdomen. Inflammation here can mimic appendicitis, producing right-sided pain, tenderness, and sometimes fever. The key difference is the timeline: Crohn’s pain tends to develop gradually over weeks or months, often accompanied by chronic diarrhea, weight loss, and fatigue.
Imaging may reveal thickening of the bowel wall in the right lower abdomen with “skip areas,” meaning patches of inflammation separated by healthy tissue. Blood markers for inflammation are typically elevated. Crohn’s disease is a chronic condition managed with medications that reduce inflammation, not surgery in most cases.
Muscle Strain and Other Causes
Not every pain in the lower right abdomen comes from an organ. A pulled or strained abdominal muscle can produce localized pain that worsens with movement, twisting, or sit-ups. This type of pain usually has a clear trigger, like heavy lifting or intense exercise, and tends to feel more superficial than deep organ pain. It hurts more when you tense your abdominal muscles and doesn’t come with fever, nausea, or changes in urination or bowel habits.
Mesenteric lymphadenitis, where lymph nodes in the abdomen swell due to a viral infection, is another cause that can closely mimic appendicitis, especially in children and young adults. It typically follows a recent upper respiratory infection and resolves on its own.
How Doctors Pinpoint the Cause
A CT scan is the most accurate imaging tool for evaluating lower right abdominal pain. For appendicitis specifically, CT scans have a sensitivity of about 97% and a specificity of 96%, meaning they catch nearly all true cases while rarely producing false positives. When contrast dye is used (both intravenous and oral), accuracy climbs even higher, to roughly 99% sensitivity. Low-dose CT scans, which use less radiation, still perform well at around 93% sensitivity.
Ultrasound is less accurate overall, with sensitivity around 82% and specificity around 86%, but it’s often the first choice for children, pregnant women, and young women with suspected gynecological causes because it avoids radiation exposure entirely. In many emergency departments, doctors start with ultrasound and move to CT only if the results are inconclusive.
Signs That Need Immediate Attention
Severe pain in the lower right abdomen warrants prompt medical evaluation regardless of the suspected cause. Specific warning signs that call for an emergency visit include pain that started mild and is steadily worsening, pain that spreads upward toward the chest, neck, or shoulder, vomiting blood, blood in your urine or stool, fever or chills, shortness of breath, extreme lightheadedness or fainting, or yellowing of the skin or eyes. Pain that doesn’t go away or keeps returning, even if it’s not severe, also deserves medical attention rather than a wait-and-see approach.