Once men get to about 30 - 35, we begin to develop problem areas which had gone un-noticed in our earlier years.. I noticed "moobs" recently, they jiggled in the bathroom mirror as I was brushing my teeth! I also get a bit pudgy in the love handle area which I am aware of these days.
In answer to your Q, move more and eat less. Chest press, dips, free weight fly exercises, push ups and cardio work will help shape the chest muscles and burn away fat. Look at your diet, cut out processed food and lower your intake of saturated fat, salt and sugar.
Give it 3 months and you should note a change