I Am A 29 Year Old Female With No Children.

I am a 29 year old female with no children. I need some advise regarding symptoms. I have never had major health concerns before and I've been experiencing pain in my left lower back for nearly 8 months. I was diagnosed with three derrmoid cysts on my right ovary in June, two small ones and one measuring almost seven inches. After three ER visits, two of which were for acute pain in my left lower back, I was told that it was due to the tumours pushing on my kidney as the untrasounds and MRI showed nothing w on with my kidney. During the entire period of June and July I was told that there was blood in my urine. The cysts were removed in September but the pain on my left side was still coming and going. Before I left the hospital I was no longer showing blood in my urine. The pain in my left lower back continued to come and go. My gynaecologist sent me for further ultrasounds in December which showed nothing. The last week of February the pain became actute to the point that I almost returned to the ER. I visited my family doctor today and was told that there is a small amount of blood in my urine. He is sending me for another ultrasound next week. I'm not sure what my the cause is and am becoming concerned. Any advice would help.