Originally Posted by ranaseagoddess
Can anyone tell me why I have two mailboxes on my device that contain the EXACT same messages
They don't unless you've never received an SMS, MMS, PIN. Messages also stores call logs (if turned on), saved browser pages, saved browser requests and several other items I can't think of off the top of my head. The icon for your email account won't contain any of these.
As stated above, hide one or the other if it bothers you.