Muscle and joint pains are commonly associated with a range of medical conditions, according to MedlinePlus. The most common causes for muscle aches include sprains, strains, using a muscle excessively, tension and stress. For joint pain, common causes include osteoarthritis, tendinitis and bursitis.
Other causes of muscle pain include adverse reactions to both legal and illegal drugs, dermatomyositis, electrolyte imbalances, fibromyalgia and infections. Additional causes include lupus, polymyalgia, polymyositis and rhabdomyolysis.
In comparison, other causes of joint pains include fractures, infections caused by viruses, osteomyelitis, septic arthritis and unusual exertion and overuse. Additional causes include chondromalacia patella, gout and pseudogout.