Hi I m 26 year old female. For the last couple of months I have had a very sore right armpit and small lump (lymph node) that becomes swollen. This happens around the time that my period is due. Once my period ends the swelling goes down. The next stage is then pain that almost curls around my breast (this pain comes and goes throughout the day) I also feel pain in my back/ shoulder blade on the same side. I m a healthy woman with no other symptoms. My GP took blood tests which all came back normal and I have had a chest X-ray which was normal. Please advise.