I'm A 32 Year Old Male. Two Days Ago, I

I'm a 32 year old male. Two days ago, I noticed my left nipple was tender and sensitive, but thought nothing of it. Yesterday, it worsened and I discovered a minor bump on the upper part of my left areola. Today, the pain is a bit more severe (still mild), and there is a red rash aroundyou breast and underarm. What could this be?