Girls fight about lots of things mainly boys (girl A finds out her friend, girl B, was dating girl A's boyfriend and then blaims girl A's boyfriends cheating on girl B) we also fight about rumors, whos friends with who, all sorts of things
If you fight a lot with a girl then you two probalbly aren't meant to be friends or in a relationship. Hang out with people that you have fun with, not ones that anger you.