--while you're checking out our Neuropathy forum, keep in mind that you could be "co-morbid"; the attribution of your neuropathy solely to diabetes may not be the whole story.

There are over 200 potential causes of neuropathy--nerves are easy to damage--AND the symptoms of nerve compression in the spinal cord, or central pain syndromes that stem from the brain, can have symptoms that exactly mimic peripheral problems. This is why it's so hard to parse out the cause(s) of widespread neural symptoms, and why it often involves a very long and detailed testing protocol.

In the Useful Websites part of that forum, there are several protocols for testing for neuropathy cause; you can definitely compare them to tests you've had and see if more investigation might be a good idea. It's been my experience that unless you've been tested at a major academic center with a good neuropathy department (and there aren't that many of those), testing is often spotty and incomplete, leading to presumptions or even the dreaded "idiopathic" designation.