This web site under 'neuropathies' is a good starter:
http://neuromuscular.wustl.edu/alfindex.htm#N
This is a set of 'guidelines' for diagnostics:
http://neuromuscular.wustl.edu/naltbrain.html
This in combination with Liza Janes' worksheets up in the stickies can help you decide how thoroughly you've been tested and also keep track of the testing...which can be quite confusing, especially when you hurt!
Since your neuropathy and pain is more 'progressive' than a normal or 'stable' type of PN, you mite want to get copies of what testing has been done to date [mite cost you some $?, but worth it!] and go and get a second opinion from another doctor, either in your area or elsewhere. You've not likely been thru the basic testing yet to say go to the Mayo or elsewhere yet.... Besides it costs too much for starters.
As Echoes said, walking on broken bones is a good description. I even once considered amputation as the pain was soo bad, but decided the 'phantom pain' of such procedures wouldn't make a lot of difference.
Pain killers don't do much for me anymore, the pain is habitual and constant. Just try and keep MOVING as much as you can for as long as you can tho.. I don't know about you? But wheelchairs really aren't my style, nor are they 'easy to use' out in the real world!
So GO! and seek another opinion and at least know what you will have to deal with? And don't write off autoimmune possibilities, as at times, they don't show up rite away. Sometimes it can take two years to show up. Further? Is the IBS under control? That could be considered a 'toxic' aspect to your neuropathy - Don't be afraid to ask questions. Folks are GOOD here, they know pain. And, how best to deal with it! Keep plugging away, we all are - 's - j