Sex is very painful for me for a variety of reasons. At one time I did have an infection that went undetected for awhile because I had a yeast infection as well as the other. It's common for it to hurt a little, but you aren't going to know why without going to a doctor and them checking it out. It could be something easy to fix. I would encourage you to work in therapy on getting to the point of having a doc take a look. It could be infection, could be your hymen isn't broken or is barely broken, could be tightness, lack of lubrication, and many other things. For me, I've been to several docs and none of them will put a diagnosis on it, but they can identify where it hurts when I tell them and there is no visible reason for it and swabs show nothing wrong. I've learned relaxation techniques in therapy but the most helpful thing has actually been **** desensitization cream. But I recommend not going that route before discussing it with a doc and finding out if there are easy answers.