What Causes A Nipple Area Lump With Soreness And Pain?

Hi, I am a 33yr old african american male and recently started to notice that I have a small lump in my right nipple area, it is a little sore to touch at times and I asked my pcp to check it and he just lightly pressed on it and like brushed it off. I am a little concerned cause I never had anything like this before and it hurts to even lay on it sometiimes, what could it be? Or what should I do?