Pain that stays in your pelvis for months is never normal and always deserves investigation.
Behind it there may be endometriosis, chronic inflammation of the cervix or endometrium, myofascial pain of the pelvic floor, nerve entrapment, interstitial cystitis or digestive problems, and often several causes at once.
Noting when the pain appears and how it changes with your cycle helps a great deal. Treatment is multidisciplinary and adapted to what we find.