Bro in all honesty U need to get on a full body routine3-4 days a week with cardio cardio cardio & DIET DIET DIET,,,,, DID U READ THAT! THAT IS UR ANSWER....
Just doing wide bench shoulders & back will even out ur symetry when u start to put on muscle & get into shape.... It's Powerlifters gut (as stated before) u are talking about & it aint gonna happen to u