So, I received a dividend notification a few days ago and managed to get access to my account via password recovery. However, I need a PIN of some sort to withdraw or transfer my shares. I'm confused. Didn't even know an account had been created for me.

Check your junk folder for the email sent to you when the account was created. That will have your PIN in it. If that doesn't work you'll need to contact burnside and he'll resend the email to you.