OSX asking for my password
As you phrased this, it generally occurs because the login password was reset at some point, and now the "login" keychain is protected with a different password than the account as a whole. The other possibility is that the keychain is set to lock automatically. Both issues can be addressed using Keychain Access, which lives in your Utilities folder.

If you do not know the password:


Choose Preferences from the Keychain Access menu.
  
Click Reset My Default Keychain
  


If you do know the password, but Keychain is auto-locked


Highlight the "login" keychain on the left of the main window.
  
Choose Change Setting for keychain "login"… from the Edit menu
  
Adjust settings as desired. By default, keychain does not lock automatically.