Cysts?

Kady
My partner and I have been trying to conceive since November 2013. Prior to that I had the ParaGuard IUD, which I had put in around March 2010 when I was 18. I had been experiencing a sharp pain in my left side for several months before the IUD's removal.
The pain has continued and gotten worse, so I recently had an ultrasound and discovered that my Left Ovary was twice the size of the right and had evidence of cysts. It is only ever consistently (every month) the left side. 
Has anyone else experienced this and if so, how did you resolve the issue? To have been using a hormone less birth control method so that it wouldn't affect our ability to start a family, and have been trying for so much longer than anticipated ... It's very disheartening. 
I don't think it's PCOS as I have none of the other tell tale symptoms...