What Could Cause Persistent Pelvic Pain For Six Months With Sudden Frequent Urination?

Hi, I’ve had persistent pelvic pain for over six months. Started when I all of a sudden needed to pee every 15 minutes for two weeks straight in August. Doctor said it wasn’t a UTI. It never/doesn’t hurt when I pee. Female, 23, 5’2, 110 pounds, no medications.