What Are The Side Effects Of Mini Pill?

Age : 17 Height : 165 Weight : 7st 9 Hi there, i am on the mini pill and felt a soreness in my breast and it felt firmer and i felt a small bump. i went to the doctor and she said it was just breast tissue. It s now only sore to the touch but im just wondering if the firmness is just the pill side effects? When i lay down there is no bumps or anything its only when standing?