There are some studies that show morphine in combination with Gabapentin to be effective for neuropathic pain. Effective in a study like this means that at least 30-50% of the subjects showed improvement. Nothing takes away all of the pain all of the time, or works for everyone, but it has worked well for me for several years. I have CMT, with significant muscle wastage so some of my pain is muscular, some is arthritic, and the rest is neuropathic.

I do not know if you have tried combining medications, but from what I have read most neuropathy sufferers end up on a cocktail of several medications, one rarely seems to do the job well enough for a decent quality of life.

I believe there is something out there that will work, but too much depends on the knowledge, creativity, and compassion of your doctor. I hope you get relief, and soon. Prolonged undertreated pain seems to be a problem all it's own with serious consequences.