Were you on Plaquenil? We have another poster here with body burning pain, that followed major itching from Plaquenil.
Or Arava? This is a known PN causer.

Can you tell me what you were taking? and are taking now?
You can do this via PM if you prefer. Some drugs have a reversible history for PN and others do not, as yet have that data.

Muscle cramping can be due to low magnesium. Do you use a good magnesium supplement or have you tried epsom salt soaks?

RSD is also a central pain condition. Some of the members there are doing a special treatment called tDCS that is electrical and done on the scalp to reset pain pathways in the brain:
http://neurotalk.psychcentral.com/thread160980.html

With RSD in the periphery, this electrostim process is only done on the head. You might want to read about it too. I've been watching it myself.