Dumb question from me but where does it say Paul was a bishop? I know he was an apostle but I can't find where it says he was a bishop.
It's not dumb at all. I believe someone cited a verse earlier, but I hope you will forgive me for not looking it up right now, as I'm getting ready for bed. (Mass in the morning, you know!)
But the bishops are successors to the Apostles, as can be seen in the passage concerning the election of Matthias in Acts. So all Apostles are bishops; in fact they are the original bishops. As you know, St. Paul wasn't one of the Twelve, but claimed the title of Apostle (for he certainly fulfilled that role), and that was acknowledged and accepted by the Eleven. So, having been an Apostle, St. Paul was automatically a bishop.