We have a Secret Question section in the account setting page.

But it is always advised not to set anything. This is a useless feature because if you try to recover your password using Secret Question then the system locks the account. I think theymos changed it for some reason.
With OP I suspect this is exactly what happened. He had his Secret Question active and he used it to recover his password and that triggered to lock his account.
Anyway, you can try this too:
Try using the
email password reset. Check that the email isn't ending up in your spam folder. If that doesn't work, email
recoveries...@bitcointalk.org, ideally
from the account's email address. Include your
username. A signature will likely be required (see below).