The way you describe eyour pain it kind of sounds like thoracic outlet syndrome...{TOS}.
have you ever had any repetitive strain injuries?
hand , arm or neck pain?
we get the knife in the back pain & some have had spasms in the rib muscles that will affect the inter coastal nerve. causing rib/chest pains and deep breathing problems.
If you would like to learn more about TOS see our forum about it -
http://neurotalk.psychcentral.com/forum24.html
It does have quite a few symptoms in common with FM - esp the myofascial symptoms.