Not really gyno, but you are predisposed to store fat in your chest. This sucks, I know because I easily store fat there also. Yes, you need to put on some lean mass, but you also need to be careful in the process. Most guys can get away with getting a little fat as they store it mostly in their gut. You'll certainly put on some fat during a "lean bulk", but this can be controlled. You'll need to eat clean and do one or two HIIT sessions per week.
Increase calories, particularly protein, and shoot for about 0.5lb per week increase in scale weight. If your not gaining at that rate, add more food. On the other hand, if you're gaining more, cut back your intake. This is the "slow and steady" approach.
I'd recommend you do a whole body routine, three days per week (look into Starting Strength). Focus on getting stronger. With the correct nutrition the lean mass will come.