A 37 yrs old female, m/f 5 yrs,  p3+0,  prev 1,  2 SVDs. lmp 27/05/16,   3/30 regular cycle h/o chronic mild pain right lower abdomen  for 2 yrs coming every 2-3 months   taking diclofenac sod tablet for pain and pain settled before. She came in the emergency ward with increased pain right lower abdomen for 1 day of such increased intensity that could not sit. Exam: Right iliac fossa tenderness present Her pelvic USG shows bulky uterus with no adnexal pathology and  abdominal ultrasound is unremarkable.

pregnancy test is negative. Kindly suggest d/d.