painful lump in underarm

Hi,

I am a 31 year old female. Cancer, including breast cancer, runs in my family. About 1 month ago I noticed a lump in my underarm that was non painful, the skin above the lump was pinkish. I have clear discharge coming from my nipple (on the same side) and the nipple area is very itchy and skin is peeling/flaking off of it. I was sent to a breast clinic. The doctor said the clear discharge is fine, and to put Benadryl on my nipple, which hasn't helped at all. He said that the lump is in my lymph node and ordered an ultrasound. During the ultrasound the lump could be felt but "didn't show" in the ultrasound. It has now gotten bigger and is very painful and tender.  No oozing or head forming on it but the skin is becoming a brighter pink. The doctor at the breast clinic said that it is "most likely" just a cyst.I have a cyst in my left breast- and it is nothing like this.  Is there any other testing that I should have or any symptoms that I need to watch for?

Thanks so much!