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A ruptured ovarian cyst could have caused scarring and adhesions. This could be causing the pain. This can be diagnosed only by laparotomy. It can also be due to appendicitis, missed on ultrasound because of bowels covering it. Other causes of lower right abdominal pain are Crohn’s disease, diverticulitis, infection in kidney, kidney stones, constipation, ovary involvement in women (cysts, hemorrhage, tumor, torsion—torsion is a medical emergency—this has apparently cleared up but it would be better to retest), mesentry (a thin tissue that carries the blood, nerves and lymphatics for the intestine) involvement due to low blood supply, enlarged lymphnodes, and an abscess in rectus abdominis muscle or psoas muscle (these two are unlikely is there is no localized patch of heat or lump). It can also be due to inguinal hernia. Other than that at times pelvic inflammatory disease causes a lower abdominal pain along with a pelvic pain. All these conditions will need to be ruled out one by one. Hope this helps. Take care!