ovarian cysts?

I have severe pain in my both my ovaries almost on a daily basis. The pain started about a 1 1/2 years ago. The only way to describe it is it feels like my ovaries are full and they are going to burst. It is pain and pressure. I have been to the doctor about it. I have had two ultrasounds done and a CT scan. The first ultrasound showed a cyst on the right ovary and nothing on the left. The CT scan showed that I had a cyst on my left ovary and an infected or hemmoraged cyst on the right. The cysts have not been huge. They haven't been over 4 cm. The ultrasound two weeks after the CT scan showed the exact opposite. My doctor put me on the pill but it didn't change anything. I am 27 years old. I have had three children and a tubal ligation after my third child four years ago. Should I be concerned? Or is this normal?