Ann is right about naproxin being sold over the counter. And Dr.P is right about the fusion issue.
Basically, It is a great anti inflammatory, but as far as covering disc pain, it's pretty useless, imho. is the Kadian helping? Thats more in line with what one would expect to use to treat disc pain.
Good luck and let us know what happens. sounds like you have an MRI in your future. Make sure all your doctors are aware of every med you are on, even if something is avalible over the counter, it could still be counter indicated, so every doctor you see should have a complete list of your meds, even vitamins and herbal suppliments.