Chest exercices

There's a lot of different exercices you can do to workout your chest. 

As a person who doesn't workout very often, nor intensely, I tend to do plank rotations. Push ups are also a great option but it's very hard and tiring. If you have weight, you can do bench press since it's very effective (but also very hard). But don't push yourself too hard and be sure to have the good posture.