What is myalgia and how is it treated?

Myalgia is muscle pain. Its treatment depends on the cause.
When myalgia is in just one area, some of the most common causes and treatments include:
injury – application of cold; rest
overuse or strain – application of cold; rest balanced with gentle stretching exercises
muscle cramp – stretching, hydration with electrolytes (if related to dehydration), massage
When myalgia is in multiple areas or throughout the body, some of the most common causes and treatments include:
infection, especially viral – fluids, anti-viral medications (for certain viral illnesses), acetaminophen, over-the-counter treatments based on symptoms
certain medications, especially statins – consider stopping or changing medication (under supervision of prescribing medical provider)
fibromyalgia – exercise, improved sleep, prescription medications (such as amitriptyline or cyclobenzaprine)
myalgic encephalomyelitis (chronic fatigue syndrome) – exercise balanced with rest, heat, acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), muscle relaxants, amitriptyline or cyclobenzaprine
myositis (muscle inflammation), such as dermatomyositis or polymyositis – corticosteroid and immunosuppressive medications
polymyalgia rheumatica – corticosteroid medication
hypothyroidism (underactive thyroid gland) – thyroid hormone replacement therapy