Sex is too painful for me

Dear Pastor,
I am 19 and I have a boyfriend. He is the third man in my life. I did not have any problems with the other guys when we had sex. 
I started to have sex when I was 17. That first guy and I broke up because he went to live with his parents abroad. The second guy and I could not get along because when we met, I was 18 but he did not want me to go out with my friends. He was always accusing me of having other men with him and that was not true.
My present boyfriend is twice my age. He is very helpful to me. He gives me everything that I ask him for. But every time we have sex, I suffer much pain. The first couple of times we had sex, I thought that it was because his penis is big, but that does not seem to be the problem. I have been telling him that we should stop having sex for a while but he does not want that. I asked him for money to go to the doctor and he agreed that I should visit the doctor. But I am asking you, why do you think I am having pains after having sex?
T.

Dear T.,
What you are asking me is what you should discuss with your gynaecologist. 
In fact, you should have already seen the gynaecologist who would determine whether you are suffering from some type of infection that might be causing pain after sex. My understanding is that there are many reasons why a woman may suffer pain after sexual intercourse. Therefore, I do not think that you should delay in seeing your gynaecologist. Do so right away. I wish you well.
Pastor