I too have that problem.Right sided rib resection for TOS....Cannot let arm hang down for long as turns blue just like beofre surgery.I use a sling for short period to alleviate the discoloration.I know not to use sling to much as will stiffen up shoulder joint but if I dont the pressure is to much.
I guess patience is a virtue with this disorder...takes a looooooooooooong time to feel more like ourselves.