Painful sex positions?

Hi guys, I was just wondering if any of you have experienced painful sex and if so, was it during any specific sex position? I'm not saying I always have painful sex, but it usually happens during missionary if I don't lift up my lower back enough. Doggie style also hurts if the penis goes in at a certain angle. The positions that feel best for me though are when it goes in through the back like spooning or him on top of me with my belly down or even standing up with my butt against him. I know it's probably my cervix getting hit at certain angles, but why does this happen and can this be prevented or is it something you just have to work around?