Sex trouble?

Okay, so I've heard that this happens for many girls, but it still kinda worries/ bothers me... Well, I really enjoy having sex with my boyfriend, but I can't really get any physical pleasure from it. With PIV sex, it usually alternates between being  painful/uncomfortable to not really feeling anything at all, and even when he goes down on me, as much as I love it, it really doesn't do anything for me either. I mean, I can orgasm on my own, but I have never been able to with someone else. Is there anything I can do to fix this and maybe enjoy sex more? I'd really love to share that experience with him. Thank you!(: