What is the cause of muscle pain after using methylprednisolone for a period of time?

Methylprednisolone is a glucocorticoid. Glucocorticoids, statins, aspirin, hydroxychloroquine and procainamide are prone to drug-induced myopathy producing symptoms of muscle pain and weakness, which most often occurs in the muscles of the extremity area, hence the symptoms of muscle pain after methylprednisolone administration.