Your cervix is more sensitive when you are pregnant. That could be the reason why it's hurting. But you can talk to your OB next time you see him/her if you are worried.
Mine does too after we are intimate. I would describe mine more as discomfort and pressure. Then again in my situation my husband is only home a few days a month if I am lucky, so my body isn't used to that like normal.
Re: slight pain....