What Does A Swollen Lymph Node In The Left Armpit Indicate?

Hello. I have a lump in my left armpit. It doesn't hurt. I was told, by a dr who didn't really look, that it was probably just a swollen lymph node because at the time I had a double ear infection and it would go away; however, that infection was almost a year ago, the lump has actually gotten slightly bigger. I do have a family history of breast cancer. I wanted to know if this is something I should be concerned about. I know it's not the most common place to find breast cancer, but it still is a little unsettling.