I don't know where you're from, but here in Canada the medical system is a joke. I also suffer from chronic pain and take opiate painkillers, and conventional medicine really has nothing else to offer in this field.
Have you tried acupuncture? I'm about as sceptical as they come about anything including alternative medicine, but what can I say? It works! I finally tried it out of desperation and I found it brought longer, more effective pain releif than massage, physio, or chiropractic.
Cannabis may be a solution for you too. For some (like myself) is offers little to no relief, but for most it offers substantial relief that it sometimes supperior to opiates. I know a lot of people aren't crazy about the idea, but it's better for you than opiates, and a lot less addictive (not at all addictive for many, including myself).
If you don't like the idea of smoking, you can buy a vaporizer. It's a device that heats the plant matter to a point where it releases the chemicals in a hot vapor into the air. Because it's heated enough to be released, but below the point of combustion, you don't get any of the tar and carcinogens found in smoke. There are varrying qualities of vaporizers, however. A "Volcano" is your best bet, with the highest quality delivery and zero carcinogens/tar. With a lower-end vaporizer you may still get some of the nasties from smoke, but it's still substantially better than smoking.
Good luck to you. Feel free to PM if you're in need of advise or support, I know how exhausting chronic pain can be.