What Causes Milia In Breast Area?

I developed what appears to be milia in between my breasts about two weeks ago, it sits above my bra line, I have not started any new clothing detergent, soap, lotion or perfume. It does not itch, sometimes they will form whiteheads. I have been using a pharmaceutical grade acne cleanser in hopes to clear it up, it will seem to almost go away but come back. Sometimes they get red, I do not notice myself sweating throughout the day but it could Be possible. I am of average weight, could this be an infection or something requiring medical attention?