Muscle Soreness Without a Workout: 8 Possible Causes
Health ConditionsOrthopedic Conditions

8 Reasons You Could Have Sore Muscles Without Working Out

Having sore muscles you can't trace to a workout might be your body reacting to stress.
8 Reasons You Could Have Sore Muscles Without Working Out
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By
Jaime Osnato
Updated on August 6, 2025
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Sore, fatigued and achy muscles are often caused by exercising harder than usual or trying a new activity. This is normal and generally feels better with time.

 But if you haven't worked out recently, muscles that hurt for seemingly no reason could be an indicator of an illness or other health condition, especially if the pain or soreness doesn't go away.

If you haven't exercised recently, and you have sore muscles for no reason or pain lasting more than three days, it's time to visit the doctor to rule out underlying medical conditions. Here are eight possible causes of muscle soreness that are unrelated to exercise.

1. You Have a Viral or Bacterial Infection

“Colds, viral and bacterial infections can cause body aches,” says Gbolahan Okubadejo, MD, a New York City-based spinal and orthopedic surgeon. The reason: “The immune system sends white blood cells to fight off the infection and inflammation can result, leaving the muscles feeling stiff and achy,” he says.

​Fix It

To relieve sore muscles caused by an infection, Dr. Okubadejo recommends drinking a lot of water and broth and getting plenty of rest. You can also take a pain reliever like acetaminophen (Tylenol) and use a heating pad to manage symptoms as your body recovers, he says.

2. You're Stressed

If you experience back and shoulder pain, headaches, and body aches, stress may be the source of your sore muscles.

 “If you're constantly under stress, your muscles may not get the chance to relax,” Okubadejo says. That's because your muscles switch into self-preservation mode.

“Your muscles have their own self-defense mechanism and tend to contract to ward off injury while under stress,” Okubadejo says.

​Fix It

“Once relaxed, the muscles will release again,” Okubadejo says. One of the best ways to loosen tense muscles is through exercise and stretching.

 Any type of workout will help, but swimming and yoga are especially great options, he says.

3. You're Not Getting Enough Sleep

Sleep is a stellar healing environment. It gives your body the time it needs to recover from the day's events, activities, and stress, Okubadejo says.

Without sufficient sleep, your body can't properly recuperate, which can lead to aches and pains.

​Fix It

Trouble catching z’s? Okubadejo suggests the following strategies for a sound slumber:

  • Avoid caffeine, alcohol, and heavy meals close to bedtime.
  • Limit cell phone use before bed — the blue light disrupts sleep.
  • Listen to calming, meditative music.
  • Stick to a sleep schedule by going to bed at the same time each night and waking up at the same time each morning.

4. You're Dehydrated

Believe it or not, muscle aches might be a sign that you're not drinking enough fluids.

 When you're dehydrated, it interferes with normal body processes, such as delivering oxygen to the right places and digesting food, Okubadejo says.

Essentially, muscle discomfort or pain is your body's way of alerting you to dehydration and telling you: ​drink more water, stat.​

​Fix It

Aim to consume eight 8-ounce glasses of water per day (more if you work out or run for long durations) and drink a low-sugar electrolyte replacement beverage to quickly replenish lost electrolytes, Okubadejo says.

5. You Have a Deficiency

Certain vitamin deficiencies can also bring on body aches.

 For example, hypocalcemia — a condition where people have low amounts of calcium in their blood — can trigger tension in your muscles, Okubadejo says. That's because the muscles (and kidneys) depend on calcium to function optimally, he says

Sometimes the underlying cause of hypocalcemia is a vitamin D deficiency, because your body needs adequate vitamin D to absorb calcium, Okubadejo says. Similarly, if your body doesn't have sufficient red blood cells, you're most likely anemic, and this can also lead to body and muscle aches, he says.

​Fix It

Consult with a doctor who can test you for these or other deficiencies and help you determine a proper course of treatment, Okubadejo says.

6. You Have Chronic Fatigue Syndrome

If you experience muscle pain and soreness in addition to unusual headaches, difficulty sleeping, trouble concentrating, and severe exhaustion, chronic fatigue syndrome — also known as myalgic encephalomyelitis (ME/CFS) — could be to blame.

ME/CFS is a serious, chronic illness that affects different parts of the body (including your muscles and joints) and is not improved by bed rest.

​Fix It

If you think you may have ME/CFS, see your doctor, who can perform an exam and diagnostic tests. While currently there is no cure or approved treatment, your medical provider can help you develop a plan to manage your symptoms.

7. You Have Lyme Disease

Muscle and joint aches can also be an indication of Lyme disease, a tick-borne illness caused by the bacterium Borrelia burgdorferi.

 “With Lyme disease, musculoskeletal interference, particularly arthritis, is common,” Okubadejo says.

“Early in the illness, patients may report ‘traveling’ musculoskeletal pain in muscles, bone, joints or tendons,” he says.

​Fix It

Consult with your medical provider, who can assess you for Lyme disease through diagnostic tests and treat you with antibiotics.

 Your doctor may also recommend topical anesthetics such as lidocaine or anti-inflammatory agents to help relieve muscle pain, Okubadejo says.

8. You Have Fibromyalgia

​"​Those who experience aches and pains for a long period of time with no known cause might [have] fibromyalgia," Okubadejo says. Fibromyalgia is a chronic nervous system condition that causes widespread pain and tenderness in muscles and joints.

What's worse, the constant discomfort also makes it hard for people with fibromyalgia to get adequate rest, resulting in sleep deprivation, Okubadejo says. As mentioned, this can play a part in sore, achy muscles.

​Fix It​

“Both the cause and the cure for fibromyalgia are unknown,” Okubadejo says. “If you think you have fibromyalgia, see a doctor for help in dealing with this condition.”

A medical professional may prescribe medication along with regular exercise, diet, a good sleep routine, and therapy to help relieve symptoms.

The Takeaway

  • If you're experiencing muscle soreness without recent exercise, it could be due to underlying issues such as infections, stress, or nutritional deficiencies.
  • Underlying conditions such as chronic fatigue syndrome, Lyme disease, or fibromyalgia can cause persistent muscle soreness that may require medical evaluation for proper management and symptom relief.
  • Talk to your healthcare provider if you have muscle pain seemingly without a cause for at least three days.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Pain and injuries after exercise. National Health Service. February 6, 2025.
  2. 10 Strange Things Stress Can Do to Your Body. Cleveland Clinic. February 8, 2023.
  3. Muscle Stiffness. Cleveland Clinic. July 20, 2023.
  4. Sleep Tips: 6 Steps to Better Sleep. Mayo Clinic. January 31, 2025.
  5. Salamon M. The truth about nutrient deficiencies. Harvard Medical School. June 1, 2022.
  6. Chronic fatigue syndrome. U.S. Department of Health & Human Services Office on Women's Health. February 22, 2021.
  7. Lyme Disease. MedlinePlus. June 25, 2024.
  8. Reid P. Fibromyalgia. American College of Rheumatology. February 2025.
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Allison M

Allison M. Fout, PA-C

Medical Reviewer

Allison M. Fout, PA-C, has 20 years of experience as a Physician Assistant with a career rooted in orthopedic care. Since 2015, she has been a provider at Excelsior Orthopaedics in Buffalo, New York, specializing in sports medicine, joint replacements, fracture care, and a wide range of musculoskeletal conditions.

She works with patients across multiple age groups — from young athletes to aging adults — helping them recover function, reduce pain, and return to the activities they enjoy.

Her dedication to patient-centered care earns the trust of both her patients and colleagues. Beyond the clinic and operating room, she's involved in education and mentorship. She serves as a mentor to fellow clinicians and students alike and works as an adjunct instructor of orthopedics for the PA program at Daemen University, guiding and empowering the next generation of healthcare professionals as they develop their technical skills, knowledge, and confidence.

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Jaime Osnato

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Jaime Osnato is a freelance writer and licensed social worker based in NYC. In addition to everydayhealth.com, her work has appeared in SELF, Shape, FitPregnancy and more.
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