I want to know the best option for removing a spot of very painful excess breast tissue under my left arm?

I have breast’s with fibroids that make them lumpy and the breast tissue has migrated under my arms it’s very painful on my left side I am on a thyroid med that my primary physician is working to get the correct dosage as well as being possible a new type 2 diabetic (still testing). I do take HRT because of a hysterectomy. I have controlled high blood pressure I currently see a physician for pain management for unrelated issues, yet many nights the pain under my arm is the most distracting.