I orgasm everytime we have sex and i also do that position a lot but never once had that kind of pain before, even when I told him to go gentle it was the worst pain I have ever felt
That sounds pretty normal to me, you can get very sharp pains that seem like they radiate very far when he hits against your cervix too hard. The sudden pain can be very shocking. A lot of women do not like this. Doggy style position allows him to enter in further, maybe you should try and stick to positions that don't allow deeper penetration, or tell him to be more gentle on you in the future.
Most women don't like anything hitting against their cervix because it feels extremely painful.
If you manage to get really turned on and into it, this can actually turn into a very intense all body orgasm. Your cervix ends up softening up the more turned on you get, it can actually take quite a beating the more your body tenses up and relaxes with orgasms, and that sharp pain, is no longer there, it turns into a magnificent orgasm.
The thing is, I have to be very excited or else it's just painful and uncomfortable, but when I am really excited, it's the best orgasm I ever have.