Well, you really need to go see your dr. I had a breast mass a few months back, + fam history as well. I keep putting it off, big mistake, got bigger. I went and had a mammogram and sonogram. It showed fibroadenoma but could not rule out cancer. The recommended a core biopsy that they could do there in the radiology center. However since it was so large, they recommended taking it out and doing the biopsy that way. ( I am very thin, you could see it when you looked at my breast) It was also right on my bra line on the right breast. To make this long story short, everything was fine, and I couldnt be happier that my almost third breast is gone. You should just go see your gyn or a breast specialist. Good luck.