need to find out the password for my backup which i encrypted, it is not on keychain access?

I restored my ipod and cannot remember the password for the encrypted backup,

it is not in keychain access and I’ve tried everything. i remember making it encrypted but cannot remember the password which is rare because i normally have just one or two and i cannot think what it could be...

is there any way i can get to the backup and put it back on my ipod without having to start all over again because it had apps, music, photos and all my stuff on there?

if i was going to take it into a store would i need to bring the mac which the backup is stored on?

thank you