John --
I understand what you are going through. I did not lose the SCM, but had radiation, chemo and bilateral ND Levels I through V 4 years ago. My shoulders and neck have become increasingly painful over the last couple of years. I can do things requiring movement (i.e. I can still play golf at the old level), but fairly often the aching shoulder and neck wake me up at night. My docs say just a combination of some SAN damage during the ND and radiation fibrosis. Exercise can help, but for now, it's Alleve and some stretching.