Google images to see if gyno or manboobs (or see a doctor if you can afford it/live in a country with single payer healthcare).
Less alcohol, more sleep (increase T) for the first, calorie deficit for the second.
Spot reduction is not really a thing.
With that being said, chest and arms (also shoulders) respond nicely to pullup, dip, and handstand variations, as well as hanging or dip support shrugs.
I'm mostly a homegym bodyweight dude, so I cannot say much about weighted exercises desu.