Hurts to have sex???

I've been having regular sex with my boyfriend and the other day we tried and it was extremely painful?? We used a lot of lube as well, so I know that was not the problem. Still doesn't feel like I'm expanding the way I usually do when I'm wet. Felt around n there's like a few tiny bumps close together about an inch in that are very painful when pushed?? Anyone got any idea what it is??