Pain during sex

So, I'm not exactly sure how to lead in so I'll just say it. The last time I hooked up with a guy, the sex hurt so bad. Everything was fine until he tried to penetrate me. We had to try a few different angles, and then he couldn't really get all the way in. And it hurt like hell and wouldn't et better. Eventually I had to just ask him to stop. My legs were even shaking (but not in a good way). He wore a condom, and it wasn't lubricated, so I don't know if that had anything to do with it.