5.Muscle Injury
Did you lift something that was too heavy for you? Or does your work involve a lot of repetition? If so, the cause of your muscle weakness could be a muscle strain or even a tear.
6.Multiple Sclerosis
Muscle weakness can be a sign of a serious health condition like multiple sclerosis (MS). When you have it, your immune system attacks the protective layer that surrounds your nerve fibers. This leads to a breakdown in communication between the brain and other parts of your body. Signs and symptoms of MS vary widely from one person to the next, but they often include numbness or weakness in one or both arms and legs.
