Sounds like you need to fix some Keychain Access settings. Grasping at Internet straws, but perhaps something like this will help?
https://discussions.apple.com/thread/2108355?start=0&tst...
(Fair warning, I'm presuming the back button of which you speak is a Safari back button. I have not experienced this problem myself and I have full-disk encryption on, which requires you to enter a password for most anything.)