It's possible the 'login' keychain is not your default keychain. Go to Applications/Utilities/Keychain Access. Then in Preferences click the 'First Aid' tab. And ensure 'Synchronize..' and 'Set login keychain as default' are ticked.
That will automatically unlock your keychain when you login so you shouldn't be prompted for it.
You can use the Keychain Access app to see what's in your keychain.