A week ago i noticed a yellow spot(size of a quarter)on my right breast.i cant recall bumping it. i assumed it was a bruise but it has not gone away and i cant recall it being the usual purple before?

I would: see a general practitioner for a quick look to determine if its anything to worry about

Check yourself: A spontaneous bruise could mean problems with your platelets. I recommend checking the of your body for similar types of bruises. A routine CBC should give you answers. However, I would perform a self-breast exam to make sure there are no lumps. See your PCP.