Often during sex I experience soreness in the entrance to my vagina as well as a discomfort/pain when he rubs against the top bladder region of my vagina, and I always make sure to urinate before sex. What could this possibly be from?

It could possibly be lack of proper lubrication. This can cause problems. When you mention the "top bladder portion" this would be your cervix, not your bladder.

Is the sex rough at all?

often during sex I experience soreness in the entrance to my vagina as well as a discomfort/pain when he rubs against the top bladder region of my vagina, and I always make sure to urinate before sex. What could this possibly be from?
The sex is sometimes rough, but even when it is not it hurts.

Have you had a recent physical? There may be a medical reason for this. When was your last PAP smear?