Muscle pain

So I'm just back from a vigorous session of badminton, and I'm once again feeling achy all over. But I know it's going to feel a lot worse tomorrow, and even the day after. Why?

The body takes some time to repair the damage done by strenuous exercise. It isn't all over in one night. For the same reason, they say you should do weight training every OTHER day, to give your muscles time to actually heal & grow before making them work hard again.