What Causes Pain In The Lower Abdomen?

I am 22 years old and have been having constant lower right pain for over 6 months or so (but have been in pain on and off before then). I am 5 ' 8" and 115lbs, so small and eat very healthy. My grandmother had ovarian cancer. In the past year and a half I have had 2 surgeries pertaining to ovarian cysts. The first was to drain the cyst. The second time we had to remove the cyst with half of my right ovary. I have been on birth control to help prevent them from coming back, so far I have only had one burst since the last surgery. (my second surgery was 6 months after my first and the bursting of the cyst was like 4 months after the second surgery). I have had many ultra sounds, none showing cysts even a CAT scan. I have been told that I do not have endometriosis and that possibly the only way to reduce the pain is to remove the rest of my ovary. I am very scared about this route. I went to a second doc for a second opinion but she said I had endometriosis (macroscopic possibly) and needed to be put on lupron. I do not think that is right. She did not even do an exam on me. What possibly could be causing this pain? Is there a way to save my ovary? I do have a health left one but it is scary at 22 when I do want to have children in the future, many children :).