Awkward but serious! Please help.

So here is my awkward but very serious question does any Ever experience pain during sex and i dont mean like that im not wet enough this hurts pain but your completely wet even lubed up some times but it hurts deep in your lower stomach pain, that hurts so bad that sometimes you just cant muscle through it you have to stop?  If you have have you gone to a Dr.? What is it? What do you think it is? Any tips? Its making it to where i almost dont want to have sex because it hurts so bad.  :(