Strange extreme upper back pian help!!!?

girlfriend has complained of an extreme upper back pain "left shoulder" for several days, it has progressed to her arm and neck and her range of motion is severly restricted. tried to slowly move it pain was so bad she was in tears. Strange cause pain is all on left side and isolated. head neck shoulder and chest. it's been days and is getting worse... any advice, is this seroius like heart attack?, pinched nerve? cairopractor, back specialist? family doc er stretches?