What's this movie called? It involves kids at camp I think, with a few fight scenes?

I vaguely remember it, but I know there were these two boys who didn't
get along. One of them started fights and always got beat up. There
was a scene where he saw the boy he didn't like kissing a girl he
liked through the window, while he was getting treated after getting
hurt. Later on, I think those two boys were in a sack race together or
something.

Does anyone have any idea what I'm talking about?