IM assuming you are trying to enable iCloud in settings and enable the keychain.
the keychain password may be different than your iCloud password if you are able to log into iCloud on your phone. Most people might use their 4 digit device password they used at that time to unlock the phone or the last 4 digits of their phone number or social security number. So it its different try to think of that 4 digit number you might have used. Even if you can log into iCloud Im not sure there is a way to recover a keychain password without a Trusted device unless you have a Mac as well.
YOu you can easily reset keychain in the Mac system preferences.
IF it's not accepting your Apple ID:
Did you enable two factor authentication?
If so it may be impossible without access to a "trusted device".
If... You can somehow log into https://appleid.apple.com/ you can change your info there.
IF you did not enable two factor authentication you just need your Apple ID and password.
IF you did enable two factor authentication you will need one of three things Besides the ID and password. Access to a trusted device, access to a device that has cookies stored that has logged in to https://appleid.apple.com/ or you need the recovery key that you were provided with when you enabled two factor authentication.
IF none of the previous options work I don't believe there is any way to resolve the issue.