A.P.
It sounds like to me you may be having either ovarian cysts or fibroids, both of what I've had. Fibroids usually don't require surgery and can shrink on their own over time unless there is severe pain and bleeding. Ovarian cysts may require surgery, though as they don't shrink and may even swell up even further and they may be either benign or malignant, which the ultrasound won't be able to identify. Both are completely unrelated to the IUD (which I've never had). Both are very common occurances, but you should get your doctor to give you the official findings from the ultrasound within the week.