what is a keychain password?

Normally, it is the same as the password you used to log in to your Mac. If you changed it, the Keychain password could be different.

To synchronize the two, do the following:

1. Open Keychain Access (you can get to it by choosing Utilities from the Go menu in the Finder).
2. From the Edit menu, choose Change Password for Keychain "login."
3. Type the former password of the account that you are currently logged in to, then click OK.
4. If you entered the correct password, a new window appears; enter the original password again in the Current Password field.
5. In the New Password field, type the password that matches your current account password.
6. Re-enter the newer password in the Verify field, then click OK.

Read: Mac OS X: Keychain Access asks for keychain "login" after changing login password