Pain felt in muscles is usually called myalgia. Pain can be felt in one muscle only but mostly it involves a group of muscles. It generally happens when we do such kind of physical work with which our body is not used to. Any injury to the muscle can also cause myalgia. Many underlying diseases and disorders are usually diagnosed because of myalgia so it is a major symptom of some disorders. Myalgia can also involve ligaments and tendons as well through which muscle is attached to other muscles and bones respectively.
Myalgia occurs due to following reasons:
- Tension: Muscles accumulate certain materials in case of stress or tension, which causes pain.
- Injury: Any injury to the muscle damages the muscle fibres. These muscle fibres contain nerve endings due to which myalgia occurs.
- Infections: Myalgias are the diagnostic symptoms of many infections. These include flu, malaria, muscle abscess (collection of pus in muscles), polio, etc.
- Autoimmune disorders: When our defence system starts working against our own body, certain chemicals are released in the body which causes myalgias. These disorders include systemic lupus erythematosus, polymyalgia rheumatica, etc.
- Overuse: When we do strenuous exercise or hard physical work, often microfibres are damaged in the muscles which results in myalgias.
- Certain drugs: Certain drugs can also cause myalgias. These include some blood pressure and cholesterol lowering drugs and cocaine.
- Electrolyte imbalance: When electrolytes level (sodium, potassium, calcium and chloride) is disturbed in our body, it causes myalgia.