Have you explored our thoracic outlet syndrome forum? TOS for short..
Or perhaps our CRPS/RSD or PN forums for the overall burning pain...

I've read in the past that fibro can come about after a long term /chronic injury, it wears the body down so fibro or something like it set in..

fibro & TOS share a few similar symptoms..

TOS rarely shows on MRI also.
previous whiplash/neck injuries can be a contributing factor to TOS