Muscle soreness is a common sports injury. Caused by working too hard for too long, muscle soreness is not only painful; it can also cause restricted range of motion. Muscle aches can strike during the latter stages of exercise, immediately after exercise, or 12 to 48 hours after exercise. No matter when the aches hit, there are steps you can take to ease the pain. Better yet, there are ways to prevent muscle aches all together.