A friend recently had surgery on her lower back to relieve nerve pressure. It was partly a disc problem, partly bone growth on a vertebra applying pressure to the spinal column.
The relief from nerve pain was immediate. She says it was a bit disconcerting - you expect pain to fade as things improve but this was like flicking a switch.
There is still quite a bit of discomfort from the op which will take a couple of months to ease. This is due to the extent that major muscles had to be displaced during the op. I imagine that there would a difference between neck and lower back in this regard.