When you exercise, your muscles lose glycogen which is a stored energy reserve made out of glucose and carbohydrates. That combined with micro tears in the muscle tissue results in post-workout muscle soreness. Once it sets in, you’ll have a hard time maintaining the exercising routine. It will even be hard for you to get up in the morning. Even though the pain can be quite strong there is no need for you to resort to painkillers. There are better ways to help your muscles recover.