Two days after my upper body workout I began having pain in my right armpit. Not too long after I realized there was a little lump in the armpit not a big lump but something that I don't have in the other armpit. It is quite sensitive especially when I squeeze my armpit. I read some stuff on the internet but I am not quite sure what I have yet. Has this happened to anybody else? Is it really a pulled/torn muscle or its nothing? And should I keep training?