mastectomy recovery

hi, I had bi lateral mastectomy 9 days ago and the sentinal nodes removed. I also had expanders put in. all my pin has been where the expanders are but also the pain under my arms is sooooo bad. I am really swollen. can any one tell me when i should expect the swelling to go down?I am beside myself with this pain. Its also like having sandpaper under my arm when I lift them. thanks marnz