Muscles are always constantly tearing on a very small level and this is more apparent after exercise. You may wake up early the morning following exercise and feel achy – this is a sign that your body muscles have been stretched and may even be torn or damaged. Most of the tears are on a microscopic level but this can lead to more serious aches or pain if not treated.
Imagine that your muscles are like elastic bands. When you exercise, sit or stand for long periods or damage muscle tissue, your muscle will become shorter and tight. This would be similar to an elastic band which has knots tied into it.