The other posts here are excellent and illustrate how different things can help different people.
My back problems are minor - I'm 73 and if I lift something too heavy - especially lifting the wrong way - I end up within hours with back pain. The cure for that I found is to simply rest my back - and, of course, no heavy lifting. Often when I go to sleep with back pain I wake up cured! Walking did not help me - resting my back did.
I do have carpal tunnel syndrome - that can really be very painful as well. The prescribed pain killers really helped with the excruciating pain - but only treated the symptoms not the cause - which was a pinched nerve. As my condition worsened, my pain became less - further damage to the nerves caused numbness which stopped the pain - but clearly was not a good solution!
I ended up going to a specialist surgeon to operate on my left wrist (for some reason my carpal tunnel on my right wrist has no symptoms). It worked - but not right away. The nerve was no longer pinched - but it takes time for the nerve to repair and work properly again. For me it took about 2-3 months.
It is important to get clear, detailed, instructions after surgery - I did not understand the directions and my incision got very infected. I needed two powerful anti-biotics to cure the infection which was far more dangerous than carpal tunnel - and about as painful btw.
Oh, btw -Potassium Glutamate pills help. And a chiropractor recommended Olive oil (in salads, stir fry veggies, etc.) which helps even more. The chiropractor said that Olive oil would (and does) increase the body's production of sinovial (sp?) fluid, which lubricates the joints.
To ingest Olive oil, not to rub it on your back.
I've heard acupuncture can help with the pain - not sure of the accuracy but worth checking on.
And there is mind over matter - I found that getting involved in any activity (like posting here - or watching a very interesting TV program) can help as well - I think the brain's production of endorphins is involved.