Hi and any help would be greatly appreciated , little history i have been diagnosed with nero as well as vascular tos , 6 months ago i had a rib resection , but still alot of pain in my scapula , shoulder , neck arm and chest, my arm still turns blue, and was recently dianosed with double crush syndrome as well , now they want me to do these nerve blocks what are they and what do they do i am rather scared , thanks suffering in canada