I am female. For about a week before my period, I found that I had difficulty turning my body. On the day of my period, I experienced intense and sharp pain in my lower right abdominal area in a specific area. If I am in a comfortable position, it felt as if there was a knife in there. If not, it felt as if the knife was cutting into me. On the 2nd day, I have also found that the pain has spread to my back area and I can no longer pinpoint the exact location. 30 years ago, I had an appendix inflammation but did not take out the appendix. What is the cause of this extreme pain? I have 2 fibroids on my right side and had my ovary taken out 21 years ago.