Side effect?

I've had horribly sore breasts ever since I started birth control for the first time June 21st. Is this a side effect that will most likely go away? Or should I talk to my doctor about switching pills when I go back in August? Laying on them is painful, and I'm assuming it is a side effect as tender breasts are one listed for the pill I'm on (Mononessa). I don't think it's anything serious as I just had a pap and breast exam in June.