Trouble having sex?

So me and my boyfriend have been together for just over 2 years, and we have a lot of trouble trying to have sex. It's almost as if I'm too tight. Like he'll get it in to a certain point, and then I feel a sharp pain, almost like his penis is bending? But he claims it's not. He's tried helping me "stretch" but it's still painful. Anyone else have this problem? Or know what to do about it?