Yea I just clicked the app store app on my iPhone and I had an update for one of my app. Now they all work again. Idk how that one update for an app fixed me getting kicked out of then all though
This happened to me. I was told by iTunes to deauthorise and reauthorise my account in iTunes. It stopped it for good. Until then, updating apps would fix it like you've said but then a few days later it would happen again.