How can I avoid seeing an Apple ID password field on my iPhone 5?
Instead of just canceling each time, give the app that is requesting it your Apple ID password.  The phone should remember the password for that given action and not bother you again.

Or perhaps your password has been corrupted so try going to Settings/iTunes&amp;App Store, tapping on the box that says "AppleID: youremail@some.com", and signing out and then back in again.