I've found that any of the NSAIDs get less effective after a few weeks and that rotating every few weeks helped. I used to bounce between Naproxen, Diclofenac, and Ibpruprophen. Doctors have told me that should not be true and that changing meds was less safe than sticking with one. I did it anyway to ease my pain. When I started using Etoricxib, a normal dose worked better for me than a greater-than-recommended dosage of other NSAIDs.
I finally had spine surgery here in Thailand - with a life-changing great result. Back pain sucks. Good luck.