What Causes Chest Pain And Breathless With History Of Having Lymph Nodes Removed?

3 years post mx and lymph nodes removed on left side for stage 1 invasive idc .....2 years post mx (no lymph nodes removed) on right side pre cancer cells. No reconstruction on either side. I thought I might have pulled a muscle on my right chest about 3 months ago, but it has not gotten any better. I have gotten pain throughout the entire area where my right breast used to be and now under my armpit with a sometimes full feeling under there. Also have shortness of breath occasionally and when I do, I have pain inside the right side of my chest upon trying to take a deep breath. I have a lot of anxiety about cancer recurrence so this is where my thoughts continuously go with all of this going on. Is this a possibility? Or is something else going on?