The benefit of having a mammogram given your history far outweighs the risks of a CRPS spread from a mammogram.

I have CRPS in my right arm from fingertips to my ear. I found my most recent mammogram slightly more uncomfortable than pre-CRPS, but it was brief and manageable. My suggestions would be to schedule your mammo for mid-cycle and when your CRPS is not in a flare. For me I had to reschedule my appointment once because I woke up that day in a terrible flare. When I had the mammo a few weeks later I was having an average pain day and I had no issues.