I have had armpit pain for 2 days, I thought I pulled a muscle or something. I awoke at 3a.m. and got to filling under my arm and felt a large grape size mass. I am 55 and gone throught menopause. I have been reading some of the comments and notice where you ask did you get scratched by a cat. Well I was petting my cat last Saturday about 4 days ago and she did get me good on my left thumb, it very sore could this be affection me with having the pain and the lump in my armpit? I have called my gyno. this morning, and waiting on a call back.