Muscle, why do our muscles and bodies hurt us after exercising?

The cause of your muscle soreness after exercise is a buildup of lactic acid - if that isn't the cause?

It is often claimed that the pain we feel a day or so later is a result of the lactic acid being shed in our muscles during exercise.

This is now known as a myth: Lactic acid goes away quickly. It is now believed that the real cause of this delayed onset of muscle soreness is inflammation caused by damage to muscle cells, which repair themselves after a few days.