Why does it hurt her to be on top?

Me and my girl can have sex in every position, but with her on top, she says it hurts. I was just wondering why would this position hurt?

It could be because when she is on top your di*k is going really deep inside her, maybe change the position slightly, so she isnt upright, you could get her to lean forward when she is on top, make sure she controls the speed and and how much is going in her

I had the same problem. You need to let her ride backwards for a while. That will stretch her vagina temporarily so when she turns around, your di*k can slide in for a comforting fit. She may also have a tipped uterus.