I've had breast lumps a few times and it never turns out to be anything other than cysts which are deemed "normal" for some women. Recently, I had a very large one, which seemed to change in size, shape and firmness. It was also often painful to touch or to even lay on my stomach at night. Went to the doctor, had it checked out, discovered that I actually have 4 cysts in the same area and that they are benign. The doctor opted not to do anything about them (by this time, they'd begun to shrink and weren't causing me any more discomfort).
Since my doctor's visit about a month ago, it's gone down even further. My suggestion is if you are drinking caffeine, eating chocolate, processed sugars or using an anti-perspirant --stop immediately. Caffeine is a huge contributor to breast lumps and anti-perspirants, as I'm sure you know, stop you from perspiring and trap toxins in the area which often manifest as lumps in your breasts.