Neuropathic pain

I used to be on a high dose of hydrocodone (up to 10, #10's a day) for my neuroapthy.  I would take 2-5 times a day.  I had to switch doctors and they lowered it to 6 per day.  They another switch was made by yet another new doctor and I was switched to 2-15mg of morphine per day and 3-50mg of tramadol.  This just isnt working and my doctor (actually a glorified nurse) wont change me back.  I was wondering if anyone has come across the same problem.  What I don't understand is that although I was taking a lot, the hydrocodone was working.  They said the concern was my liver, yet my liver test came back normal and ok.