Hi Judy
I have a total left vertical skin sparing mastectomy back in April and sentinel node biopsy.
Not sure if you received the BCNA DVD with post-op exercises? The first couple of weeks exercises are all about trying to stretch (gently) the area you're talking about. They are easy and customised to the kind of operation you have had and I found them very helpful.
I also returned to pilates about 4 weeks post surgery once I had the OK from my surgeon. My instructor has been working with me on the ahoulder/arm issue and it's nearly resolved now (3 months on). The only thing I seem to do is bend the left arm more than the right...like my subconscious is trying to make up for what's not there any more.
Good luck
Nikki x