They are known as fluid filled sacs or pockets within or on the surface of the ovary. It is very common in women and most women have ovarian cysts during some point in their lives. The majority of these dissapear without treatment within a few months. That is why they want to give them a chance to decrease and if they do not they will send you to a specialist to determine if they need removal at that time. In most pain free cases of ovarian cysts they do not have a cause for treatment but since you are experiencing pain they are going throught the regular course of treatment for this condition. If the cyst continues to cause you pain or they feel that it could rupture then they will perform surgery to remove the cysts to keep this from occuring. They call this a septated cyst behind the uterus (Ovarian cyst) as your ovaries are on each side of the uterus. I would follow their instructions accordingly. If your pain should increase I suggest a call back sooner to be re-evaluated for this condition. I have included a link for even more detailed information below that I feel will help you to understand this more and if you have any further questions please let me know.