I agree with Healthgirl, the skin biopsy is probably the best way to diagnose small fiber neuropathy. (even though it is not fool proof)

I think the whole psychalgia thing I think is often just the doctors taking the easy way out. I can tell you from personal experience that anxiety (or depression) can in fact cause pretty much any symptom that is regulated by the nervous system in any way (all kinds of digestive issues, headache, sweating, heart palpitations, tremors, twitches, speech issues, breathing issues, the list goes on - and yes I believe it can cause pain sensations). But I think that is highly unlikely in a person who does not have any other signs or history of anxiety or depression.

From what you describe, it does certainly sound like some form of small fiber neuropathy. Unfortunately, even with very good doctors it can be difficult to get a firm diagnosis. And even with a diagnosis, it is difficult to find the cause, and difficult in many cases to treat.

My advice (to anyone who will listen) is to start out with dietary improvements, an exercise program, stress reduction, and use of supplements as needed. You can find lots of advice on supplements throughout the forums here. No one thing works for everyone - its unfortunately somewhat of a trial and error thing.

I hope you can find what works for you, and get some relief soon.