My dad took it for his back pain for a while up until a couple of years ago when he decided to quit going to the chiropractor and saw an orthapedist (I think, musculo-skeletal-something-or-other) who basically "fixed" it in a few minutes.
He says the pain still comes back bad every now and then when he pushes himself too hard at work, but he doesn't take Celebrex anymore because he finds it works too well. It would get rid of all pain and discomfort in his back so he would worry about pushing himself too far.
So basically, he doesn't take it anymore because it works too well. The pain he got from his back on some days would be so bad he couldn't move, but he could just take some Celebrex and be back to work right away.