Hi, I noticed a lump under my left armpit some time ago that didn't seem to be tender or large, just a little different then the right side. About a week ago I had been thinking my sweater was irritating my armpit but I also noticed a tenderness on the top of my shoulder right above the bone. In the shower this morning I did a self exam and realized this lump had grown in size and moderate pain after applying some pressure. There was no known insect bite, no itching, previous injury or stiffness. I have an appointment with my doctor on Monday but curious of your thoughts and questions to make sure I ask my doctor. I have already started researching through WebMD. Thank you, Nancy