Hurting during sex


I have had 4 sexual partners (all I have used a condom with) and majority of the time that I have had sex with them it's painful. It's not the opening of my vagina or anything. I am also very wet and aroused as well so it has nothing to do with that. But for some reason when I have sex the very back of my vagina hurts and sometimes it hurts really bad. Occasionally there will be a slight, sharp pain the next day as well. I have no bleeding or anything afterwards or during sex. I do spot throughout my cycle. I am not on birth control and I use protection during sex. It starts to hurt when my boyfriend thrusts faster and even then it's not that fast or deep when he does it and I will still get those pains. I feel like if I had legit rough sex I would just start crying because of the pain. The pain is only in the very back or my vagina. When I first started having sex 3 years ago it hurt in the back of my vagina and kind of where my ovaries are. It rarely hurts where my ovaries are and majority of the pain is in the very back of my vagina. Does anybody experience this or have some idea of what this could be? I feel like I can't let myself or my boyfriend enjoy sex fully because of the pain sometimes.