I have had the same queen-sized mattress for almost 11 years now (yikes!). It's getting to the point that when I roll over in the middle of the night (I'm a bit of an active sleeper) I can hear my back crack in like a dozen tiny pops. And I have back pain almost every day. We're looking to FINALLY replace our mattress this year — does anyone have any recommendations on the best mattress for back pain, or for active/combination sleepers?