It’s probably no big surprise when your muscles feel stiff or sore the day after you deep-clean your house or give your treadmill a run for its money. Those are the kinds of aches we all might feel after we’ve moved our bodies a lot.

But other muscle pain is more mysterious. You might wonder why your muscles ache after a simple stroll around the block or why you still feel pain after a few days.

When your muscle pain doesn’t go away or you’re not sure of the cause, it’s a good idea to talk to your doctor. “Everyone who has muscle pain deserves a full medical workup,” says Nilanjana Bose, MD. She’s a rheumatologist at the Rheumatology Center of Houston in Texas.

Here’s a look at why muscle pain can happen — and what to do about it.

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What exactly is muscle pain?

It’s your body signaling to you that there’s a problem. Depending on what’s behind it, your muscles can feel sore, achy or crampy. Or the pain could be sudden or sharp. Some people feel muscle pain only in specific areas of their body, while others feel it all over.

The origin can vary, too. Muscle pain can come from within the muscle itself or from what surrounds it. That includes ligaments, tendons, bones and the soft tissue that connects the muscles, says Alka Gupta, MD. She’s a clinical assistant professor of medicine at Weill Cornell Medicine and chief medical officer of Bluerock Care in Washington, D.C.

What causes muscle pain?

Muscle pain, also known as myalgia, can have many causes. Some are related to activity or tension. Others can result from illness, injury, infection or even the side effect of a medication.

The simpler and less serious causes of muscle pain usually clear up within a few days or weeks. And the pain is typically contained to a specific set of muscles.

Those causes can include:

  • Delayed-onset muscle soreness (DOMS). When you overexert a muscle, it can cause tiny rips or tears. To repair those tears (and come back stronger), your body sends more blood to the muscle.

    “All of this causes swelling in the muscles, which causes the soreness,” says Dr. Gupta. DOMS usually goes away after a few days and can be eased by taking over-the-counter pain medications such as acetaminophen or ibuprofen. Icing and light massage can help, too.

  • Stress and tension. Deadlines, traffic, figuring out what’s for dinner. When we feel stressed, many of us tense up. Holding that position for a long time can lead to muscle pain, especially in the neck, shoulders and back. Taking time to relax, be it mindfulness exercises, a warm bath or a massage, can ease tension.
  • Dehydration. Not drinking enough water can cause muscle cramps, Dr. Gupta says. Fluids help your muscles contract and relax, according to the Mayo Clinic. If you notice your muscles seizing up, try increasing your water intake.

When muscle pain stems from something more serious, other symptoms often come with it, says Dr. Gupta.

Other causes of muscle pain can include:

  • Nutrient deficiencies. Many vitamins and minerals play an important role in muscle function. If you’re not getting enough of the key players such as magnesium or vitamin D, you could experience muscle cramps or pain, according to the National Institutes of Health. Another sign of low magnesium or D: excessive fatigue.
  • Fibromyalgia. It’s a chronic illness that can prompt muscle and joint pain throughout the body, along with fatigue, sleep, memory and mood issues. The exact cause isn’t known and there’s no cure. But symptoms can be eased by managing stress, exercise and diet, according to the Cleveland Clinic.
  • Colds, flu and COVID-19. These illnesses can come with a side of muscle aches brought on by your body’s immune response. With any of these infections, you could also have a fever, chills or congestion.
  • Lyme disease. This is an infection that comes from a tick bite. The overall inflammation from the infection can induce body aches and neck stiffness. (You might also have a fever, headache, fatigue or the telltale skin rash.) Here’s how to reduce your risk of tick-borne illnesses.
  • Rheumatoid arthritis. It’s a chronic inflammatory disease that attacks the joints and can sometimes bring on muscle spasms. Other common symptoms include stiffness, fatigue and painful swelling of the joints.
  • Taking statins. Several medications can cause muscle pain, such as those for treating cancer and high blood pressure. But statins, which treat cholesterol, are one of the more common medications linked with myalgia, says Dr. Bose. Some people even have to stop taking a statin because of it. We asked a pharmacist how to manage statin side effects.
  • Certain cancers. Sarcomas, which are soft-tissue cancers, can cause muscle pain if the tumor presses on nerves or muscles. Certain blood cancers such as leukemia can also result in muscle pain because the cancer reduces the amount of red blood cells the body makes. This means the muscles get less oxygen.

To figure out what’s behind your muscle pain, your doctor will usually start with bloodwork, Dr. Bose says. They will also likely ask you questions, give you a physical exam and order labs and imaging tests, she adds.

Be aware that it can take time to find the source of your muscle pain, but it’s important to stay on top of it.

“It’s not always obvious what the cause is at the beginning,” Dr. Gupta says. “So be patient with your doctor and follow up with him or her frequently to discuss your pain if it’s persistent or gets worse.”

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Additional sources
An overview of muscle cramp symptoms and causes: Mayo Clinic
Facts about magnesium: National Institutes of Health
Facts about vitamin D: National Institutes of Health
Treatments for fibromyalgia: Cleveland Clinic