I've been having the exact same problem.
I have tried all of the advice listed here and what seemed to fix the problem is to delete everything from my iPhone and set it up from scratch. However, after loading all of the aps back on one refused to update (Hootsuit for Twitter).
I reinstalled from the older backup and thinking on the list of updated apps, most have updated on their own and some need a little push. My best guess is that sometimes apps are interupted when they are in queue which causes them to stick later on. Delete the app and reload it, the issue goes away.
The point was this, I called Cusomer Support yeserday and he and I went through the list and none of it worked. He told me that I should do the reinstall and if it doesn't work it's a hardware problem. Maybe it is. If you're having trouble, see if you can get a new phone. It might be a hardware issue. I'm going to wait till after the new year to see if it works itself out.