Several months ago during a breast exam, I showed my doctor a hard lump in my armpit, about the size of a BB.
She said it was a lymph node, and to just keep my eye on it since it wasnt swollen and didnt hurt. After a sonogram, the radiologist agreed.

Now it is swollen, about the size of a small gumball, sore, and the surrounding skin is red.

I have an extended family history of breast cancer, but it is on my fathers side of the family. I have been going to the gym about 3 hours a day for the past few weeks and sweating quite a bit.

My question is; How likely is it that both the doctor and radiologist were incorrect about this being a lymphnode? I believe that it is behaving like an ingrown hair or an abcess, although it is about a half inch deep, and I can see no connecting hair follicle or pore.