Ouch! Why Does My Side Hurt?

Learn the causes of pain on your left or right side

Maybe it started off small. Maybe it suddenly came out of nowhere. But where did the pain in your side come from — and should you be worried?

“Pain in your side or in your abdomen is a common complaint, and it’s a common reason for people to visit the emergency room,” says Matthew Souder, MD, a general surgeon at Geisinger.

Causes of your pain can range from harmless to serious, and it’s not always easy to pin down what it is. Here are a few things to look out for.

What are common causes of side pain?

To narrow down what's behind the pain, Dr. Souder suggests paying attention to a few specific factors.

“If you’re having pain in your side, keep track of it and see what aggravates it,” says Dr. Souder. “Does it hurt more when you stand or sit? When you breathe in or breathe out? Does it always hurt the same amount, or is it off and on?”

Some common causes include:

Appendicitis

Pain — especially on the lower right side of your abdomen — paired with fever, vomiting and loss of appetite could be signs of appendicitis, which requires emergency medical attention.

“One of the most serious reasons for abdominal pain is appendicitis,” says Dr. Souder. “Appendicitis, or an infection of the appendix, can be a life-threatening condition. It’s a medical emergency, and surgery is required quickly to remove the appendix.”

Don’t delay treatment, because an infected appendix can burst and create serious complications.

Gas and constipation

The most common reason for the pain in your side is what you ate or drank. Gas or constipation is usually the biggest false alarm when it comes to abdominal pain. Each can cause fairly strong pain, but they usually aren’t harmful.

You can feel gas and constipation pains throughout your abdomen. They’re usually identifiable by being inconsistent — the pain may come and go, and it changes depending on how you’re sitting or standing. The pain should subside within an hour or shortly after a bowel movement.

Irritable bowel syndrome

Irritable bowel syndrome, or IBS, is a common condition that causes spasms in the large intestine. You can feel this pain throughout your belly area, but most people notice it in their lower abdomen.

“Cases of IBS can range anywhere from mild to severe, and it often runs in families,” says Dr. Souder. “Factors like food, stress and hormones can trigger IBS, causing symptoms like cramps, pain, bloating, diarrhea and constipation.”

If you have IBS symptoms, talk to your doctor. They can diagnose whether you do have IBS and prescribe medication if necessary.

Kidney or gallbladder stones

Stones aren’t just something you find outside — they may show up in your kidneys or your gallbladder, too.

Kidney stones are deposits of salt and minerals that can form and harden in your kidneys. Gallstones are deposits made of cholesterol and bile. You’ll usually feel gallstone pain on the right side, but you can have kidney stones on either the right or left side.

“Kidney stones and gallstones can cause excruciating pain,” says Dr. Sounder. “You may pass kidney stones naturally, but in more severe cases, they may require surgery. Talk to your doctor if you have severe, radiating pain that lasts for more than a day.”

Muscle or joint injuries

Strained muscles, arthritis or spinal injuries can all cause pain that spreads from your back to your side. If your pain is muscular, a combination of rest and light stretching exercises could help. If nothing seems to help, it’s time to talk to your doctor.

Urinary tract infection

When your side pain comes with painful urination and needing to use the bathroom often, it might be a urinary tract infection (UTI). This bacterial infection is extremely common, especially in women, and it’s best to see a doctor for treatment.

Shingles

Did you have chickenpox as a kid? If so, side pain might be the first sign of a shingles infection. Despite the common myth, shingles affects people of all ages, causing intense pain on one side of the body and a blistering rash.

Early detection can reduce your pain and the length of the infection — so let your primary care provider know as soon as you suspect shingles, even if a rash hasn’t formed yet.

When should I see a doctor for side pain?

Pinpointing the cause of your discomfort starts with paying attention to your body. Whether it’s something as simple as gas or more serious like appendicitis, sharing what you’ve noticed with your doctor can help them come up with the best treatment plan for you.

Sometimes it’s critical to seek care for side pain. See a doctor immediately for any of these symptoms:

Severe pain
Fever
Swelling and tenderness of the abdomen
Bloody stools
Yellowing of the skin
Persistent nausea and vomiting

“If the pain is severe or interrupting your ability to go about your day, get medical attention,” says Dr. Souder. “Even if it isn’t anything dangerous, it’s still better to be sure.”