The cause of muscle soreness may be the result of overexertion, muscle trauma, or autoimmune related etiologies. 1. Overexertion: If the patient repeatedly uses localized muscles for a long time and over-exerts them, this may lead to persistent fatigue of the relevant muscles, aseptic inflammation and lactic acid build-up within the muscles, which can lead to muscle soreness. 2. Muscle trauma: If the patient over-exercises or performs some particularly strenuous activities, it may cause injuries such as muscle strains. Muscle soreness is caused by the destruction of muscle fibers and the inflammatory response that occurs. 3. Autoimmune-related etiology: When a patient develops some autoimmune-related lesions, such as rheumatoid arthritis, his or her immune system may attack the muscles, leading to damage to the relevant structures, which in turn leads to the symptoms of muscle aches and pains. When the symptoms of muscle aches and pains cannot be relieved, or when they are accompanied by other symptoms, the patient should consult a doctor in time and pay attention to daily rest to avoid over-exertion.