thanks for ur query ur history suggests u r suffering from peripheral neuropathy diabetes mellitus is a common cause of PN u need to exclude diabetes needs to have FBS PPBS done again as ur PN is strictly confined to upper arm u need to exclude cervical rib, brachial plexopathy, thoracic inlet syndrome u should have at least a chest x-ray u need to have some physical test done, for this consult a neurologist and u also should have a nerve conduction velocity testing for the upper limb these will i think diagnose ur case need not to worry thank u