I know it can be scary, but I had something similar. For one: ask your doctor to give you a full hormone test which will test your Progesterone levels. A lot of times things like this are linked to producing too much Estrogen and too little Progesterone, and Estrogen causes growth(it's the growth hormone). This could be why he also put you on birth control, but chemical hormones are so dangerous. Natural progesterone cream has helped me to rid myself of cysts and fibroids, and it also balances out my hormone levels which aids in weight loss.
Please consider talking to your doctor about a hormone test, as well as seeking out a second opinion from another doctor. Most doctors will throw ladies on birth control, but that should never be the answer. Here is a link for a website which explains it all better: FAQ PCOS
This is the part on how progesterone can hel with POS.
I wish you luck, and will be here for you if you need to talk about it. ^_^