What is my Apple Keychain Access Password?

For you login.keychain it's usually your username/password for the Mac. The only way that would get desynchronized or non-working is if you needed to reset you local computer password for your account using a USB boot disk or or some other type of reset method, those methods usually are not able to reset the login.keychain.

Please try using the 'Keychain Access' tool - which you can get access to using the Search/Looking Glass/Spotlight button and typing Keychain Access and see if you can open up the Keychain using either your current or former computer password.

Same as your admin password.

If you are the only user then you are the admin.

To change:

 > System Preferences... > Users & Group > select admin (left panel) Click Change Password (right)