The fact that your pain disappears while taking birth control pills makes me quite suspicious that you may have endometriosis. Endometriosis can and does cause adhesions to form so if you have adhesions, this may be why.
Endometriosis has a wide variety of possible symptoms, different with each patient. One of the symptoms is bowel problems such as constipation, diarrhea, pain with bowel movements etc.
I would encourage you to consider endo as a possibility and consult with a knowledgeable gynecologist.
Good luck!
-- Debbie