You need Diet + Cardio.
Diet isnt that bad. You need to maintain a negative calorie balance. Say -500 and the weight will go down. 45 min of cardio at decent speed in morning and evening.
See if your company has a gym, cause you will need gym to do weight training to tighten up the chest. Explore online resources and popular websites, you'l know more.What i gave you is the gist.
