muscle knots

I have always wondered why i get muscle knots after working out or after a tough game. the reason for the knots to occur for example in your shoulder is because the points in your muscle are contracted fibers that cant release these can cause pain in two ways; latent trigger points which only cause pain when u apply pressure on the point or try rubbing the area, the other one is called active trigger points which cause pain rapidly and along the neural pathways which connects the nervous system with another. knot heads can either be the size of a pinhead in smaller muscles to the size of a thumb in bigger muscles