You're in a difficult situation! Have you tried Ultram? Ultram is a technically a narcotic pain reliever but it has a very very low incidence of addiction. It is often used for back pain. Its not as strong as Vicodin or Percocet or OxyContin but it should be able to give you much more relief than you're currently getting.
http://www.healthcentral.com/chronic-pain/find-drug-25432-25.html
You might also consider trying alternative methods of pain relief such as relaxation exercises meditation, biofeedback, etc. You might ask your doctorto see if your insurance covers these therapies. Since they're reluctant to give you a narcotic pain relievers one would think they have a responsibilityto try alternative means.
You can also do these therapies on your own. They work by turning down the stress response which alleviates the pain response as well. You can find a good introduction to them and exercises you can do in John Kabat-Zinn's book "Full Catastrophe Living" which you can find on Amazon.com.
Keep pushing your doctors for pain relief. Impress upon them how serious it is and that you've considered suicide because of it. Physicians are very reluctant to prescribe narcotic drugs to people they think may become addicted but if you have really severe pain addiction is a much better option than suicide!
Good luck!