Its normal when you're pregnant your cervix becomes very sensitive because of all the extra blood flow down there. Some days are easier then others. I have this problem too and it helps if the guy doesn't ram all the way back to the cervix.
That doesn't sound good at all. Consult your doctor.
Could be the position.. I noticed now I'm 10 w I have to be on top or else is to painful. That or it could just be the hormones kicking in