(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.)
This is quite possibly the case. OS X doesn't normally ask for your password once you're logged in except when you're doing something that will affect multiple users (e.g. updating the system). The big exception is when it has somehow lost your keychain password, in which case it will ask for your password every time it needs to look at the keychain.
Comments
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.)
This is quite possibly the case. OS X doesn't normally ask for your password once you're logged in except when you're doing something that will affect multiple users (e.g. updating the system). The big exception is when it has somehow lost your keychain password, in which case it will ask for your password every time it needs to look at the keychain.