It sounds like a blackhead. You can get them on the body, anywhere. Try cleansing the area with the no rinse hand sanitizer. This will kill the bacteria that is causing the breakout. Acne medication that has salicylic acid as the ingredient will work well too. If the blackheads persist you may want to see a dermatologist. Keep the area dry with some cornstarch or baby powder that is made from cornstarch. Talc can cause yeast infections on the skin so it is best to avoid it.

I have the same thing on and off for years...I pop it after its big enough...clean it well with peroxide...put neosporine and bandaid over it and it clears up..I have large breast also and don't wear a bra in the house.
aai'm sure this has something to do with it.