Hi I am a 27yr old female. I first noticed that I had what appeared to be swollen lymph nodes in my left armpit. It wasn t a major problem, Dr suggested it could be irritated from shaving, perhaps I cut myself with the razor....small infection no biggy. I soon got my period for the first time. It didn t take long to see a pattern. My left armpit would swell almost exactly a week before I got my period, EVERY time. It is so uncomfortable that I often avoid sleeping on my left side, I ll put a pillow between my arm and my body and take Advil or ice the area. I m not overly sensitive to pain, I rarely go to the Dr. Over the years I have seen a handful of family drs about the issue and none of them seem to have any ideas on what the problem could be. I was sent for an ultrasound about ten years ago but it wasn t done within the wk before my period and they saw nothing out of the ordinary. I should mention that the tenderness and swelling NEVER completely goes away but it is definitely a lot worse the wk leading up to my period. Wearing a sports bra rather than underwire helps tremendously, exercise and hot yoga seem to help. I recently had a baby, when my milk came in I had two huge extremely hard lumps only in my left armpit. It was almost unbearably uncomfortable. They eventually went away on their own but the swelling continues. The side of my left breast is also extremely tender and lumpy the wk before my period. I use a basic all natural deodorant, after about 6 months of using it I got a red raw sore spot only in my left armpit.....doesn t bother the right one at all. If I work out and am sweating I ve noticed that I smell 100 times worse out of my left armpit.....I am beside myself. 13 years this has been going on and I can t seem to get any answers.