When you did the backup to your MacBook, it would have asked you if you wanted to use a password. If you say yes it will save the passwords on your phone along with the password-protected data such as your health information. Saying no means you don't save everything, but you don't have a password to remember.
It sounds to me like you used the first option of adding a password for your backup; that's the password you need in order to restore that backup. You'll just have to figure out what you set that password to.