Being a speedskater, I know all abut back pain. I also have a bad ankle which is very troublesome.
So for decades I took heavy duty NSAID's for my ankle. But the NSAID's never did anything for my back.
Later I started taking a glucosamine/chondroitin supplement for my back. It works within hours but only lasts a about day. It doesn't do anything for my ankle.
Last year I had to stop taking NSAID's. So I switched to Tylenol which works much better than the NSAID's for the ankle but not the back.

My thought is that glucosamine/chondroitin is pain specific, either it works or it doesn't and if it's going to work on a problem, it's going to do so quickly. None of this 30 day nonsense.