The next symptom to discuss is a so-called myositis. Gastroenteritis may cause the inflammation of muscles. It makes sense that such action will lead to ache. You see, each time some virus penetrates the organism, it might produce specific substances into muscle tissues. The muscles then cannot function properly without causing some pain. As a rule, such problem is relevant for the lower and upper extremities. In the serious cases, the muscles will stop reacting, causing the limited movement.