Laying on a hard floor with my arms above my head has been my near-term way of coping with back pain. But a little isometric back strength exercises like a nightly plank have helped with prevention over the past few weeks.
I tried a solid wooden bed platform with about 2 inches of foam mattress topper. If nothing else, it makes you really good at camping - sleeping on the hard ground is so much more comfortable when you're used to it.
