I think a neuroligist can give the 'firm' dx. But my internist and the research I've done confirm it enough for me.
How many mg of Naproxen are you taking? Its like Aleve. I think uping your amitriptyline would be a help, being it is used for neuropathic pain.
Please, check out the website www.endthepain.org (TN Association) and check out the Diagnostic Questionnaire. You'll probably be amazed with your answers. I know I was.
Keep up with what your doing. Sounds like you are getting some good relief to work. I talk with customers (via phone) all day and some know me so well they can tell the difference in my voice if I am not doing to well. Having to look at customers face to face like you do has got to be real tough. You must have a good game face.
Take Care,