If anyone has back pain, then, sleeping on floor or a very firm mattress is the ONLY way you will get some relief. You must sleep on your back, or side, and put a pillow under your knees or between them if on the side.
Yeah, you actually feel more sore for the first couple of days, but then, your back pain begins to get better, and you get used to sleeping on a hard surface.
I know quite a few people that did that, and now, they don't need weekly chiropractor appointments / monthly doctor visits of getting shots. They saved a ton of $$$.
The main issue of the floor is, it is too low (duh) for lots of people.