It definitely sounds bladder related, and in that case you'll most likely have to see a Uroligist. But it wouldn't hurt to first talk to your OBGYN and see if they want to examine or refer you. They will probably want to do a urine test to check for infection.
I highly doubt this is related to intercourse. But we're all different, so your doctor would be best to tell you that.
I'm concerned about the pain. At one time you couldn't get enough, and now you're talking frequently about this pain caused during sex. Are you letting him know he's hurting you? Does it hurt every time?