The most common causes of muscle pain are tension, stress, overuse and minor injuries. This type of pain is usually limited to just a few muscles or a small part of your body.

Muscle pain that is felt throughout your whole body is most often caused by an infection, such as the flu. Other causes include more-serious conditions, such as some diseases or health conditions that affect the muscles. Muscle pain also may be a side effect of certain medicines.

Common causes of muscle pain include:

• Chronic exertional compartment syndrome
• Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)
• Claudication
• Dermatomyositis
• Dystonia
• Fibromyalgia
• Hypothyroidism (underactive thyroid)
• Influenza (flu) and other viral illness (influenza-like illness)
• Low levels of certain vitamins, such as vitamin D
• Lupus
• Lyme disease
• Medications, especially the cholesterol medications known as statins
• Muscle cramp
• Muscle strains (An injury to a muscle or to tissue that connects muscles to bones, called a tendon.)
• Myofascial pain syndrome
• Polymyalgia rheumatica
• Polymyositis (This condition inflames the body's tissues causing muscle weakness.)
• Rheumatoid arthritis (a condition that can affect the joints and organs)
• Sprains (Stretching or tearing of a tissue band called a ligament, which connects two bones together in a joint.)
• Too much or too little of electrolytes, such as calcium or potassium

Muscle pain from minor injuries, mild illness, stress or exercise is usually helped with care at home. Muscle pain from severe injuries or health conditions is often serious and requires medical care.

Get medical care right away or go to the emergency room if you have muscle pain with:

• Trouble breathing or dizziness.
• Extreme muscle weakness with problems doing routine daily activities.
• A high fever and stiff neck.
• A severe injury that keeps you from moving, especially if you have bleeding or other injuries.

Make an appointment with your health care provider if you have:

• A known tick bite or could have had a tick bite.
• A rash, especially the “bulls-eye” rash of Lyme disease.
• Muscle pain, especially in your calves, that occurs with exercise and goes away with rest.
• Signs of infection, such as redness and swelling, around a sore muscle.
• Muscle pain after you start taking or increase the dose of a medicine — especially statins, which are medicines used to control cholesterol.
• Muscle pain that doesn't improve with care at home.

Self-care

Muscle pain that occurs during an activity usually signals a "pulled" or strained muscle. These types of injuries usually respond well to R.I.C.E. therapy:

• Rest. Take a break from your usual activities. Then begin mild use and stretching as recommended by your health care provider.
• Ice. Place an ice pack or bag of frozen peas on the sore area for 20 minutes three times a day. 
• Compression. Use a stretchable bandage, sleeve or wrap to lessen swelling and provide support.
• Elevation. Raise the injured area above the level of your heart, especially at night, which allows gravity to help lessen swelling.

Try pain relievers you can buy without a prescription. Products you put on your skin, such as creams, patches and gels, may help. Some examples are products that include menthol, lidocaine or diclofenac sodium (Voltaren Arthritis Pain). You also can try oral pain relievers such as acetaminophen (Tylenol, others), ibuprofen (Advil, Motrin IB, others) or naproxen sodium (Aleve).