Hurts during sex

So i’ve only had sex a few times with a couple of different guys, and it sometimes hurts a little when i’m not wet enough but I can fix that but i’ve noticed that it hurts quite a bit when the penis is in deep, it’s fine in missionary cause it doesn’t go as deep as when i’m on top because then it really hurts and I just want to know why this might be or if anyone has had anything similar