Meaning of myalgia: Whether the ache sits in one muscle or everywhere at once is the first question, because the two lists of causes barely overlap.

Definition of myalgia

Myalgia is pain arising in muscle tissue rather than in a joint, bone or nerve. It may sit in a single muscle or muscle group after exertion or injury, or spread across the whole body during an illness. The word records the symptom alone and says nothing about the cause, and the pain ranges from mild soreness to a level that limits movement.

How myalgia is built

my algia myalgia
  • my/o Combining form · Greek muscle
  • -algia Suffix · Greek pain

A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.

What causes muscle pain?

Most myalgia is mechanical and short lived, following unaccustomed exertion, a strain or a direct blow. Soreness that appears a day or two after hard exercise comes from microscopic damage to muscle fibers and settles on its own. Beyond that the list widens considerably, and the pattern of the pain narrows it faster than the pain itself does.

SourceWhat it tends to look like
Overuse or injuryOne muscle or group, tender to press, worse with the movement that caused it
Viral infectionAching everywhere at once, arriving with fever and fatigue and easing as the illness passes
MedicinesCholesterol lowering statins and hormone lowering cancer treatments are the best recognized
Inflammatory muscle diseaseReal weakness alongside the ache, especially rising from a chair or reaching overhead
Hormone and mineral disturbanceAn underactive thyroid, low potassium or low calcium can each produce aching muscles
Widespread pain conditionsPain across many regions with tenderness outside muscle too, and broken sleep

How is muscle pain told apart from joint or nerve pain?

The site of tenderness does most of the work. Muscle pain is felt in the fleshy body of the muscle, is usually described as a deep ache or cramp, and worsens when that muscle is contracted or stretched. Joint pain sits at the joint line and hurts when the joint is moved, whether or not the muscle around it is working. Nerve pain burns, shoots or tingles, follows the course of a nerve, and often brings numbness with it. The three overlap constantly, and pain from a deep structure is frequently felt somewhere else entirely.

What is looked for when it does not settle?

Duration, distribution and company all matter. Aching that spreads across the body with fever points toward infection. Aching with genuine weakness points toward the muscle itself. Aching that began soon after a new prescription points toward the medicine. Blood tests can measure creatine kinase, an enzyme released when muscle fibers break down, and a markedly raised level indicates real muscle damage rather than simple soreness. Dark urine alongside severe muscle pain suggests breakdown extensive enough to strain the kidneys. Ordinary myalgia is usually handled with rest, heat or cold, a nonsteroidal anti-inflammatory drug and a gradual return to activity, with physical therapy where a movement problem keeps loading the same muscle.

Also known as

muscle pain

Used in a sentence

The patient reported diffuse myalgia that began several days after the onset of the viral illness.

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Good to know

Myalgia describes pain within the muscle itself and is distinct from arthralgia, which refers to pain originating in a joint.

Word origin

Where “myalgia” comes from

Formed from my-, from Greek mys, meaning muscle, and -algia, from Greek algos, meaning pain.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.