Being the smallest thing when you are with your friends is not a good thing, both how people perceive you and your self-esteem. It sucks like crazy having a figure 1 shape with no developed muscle whatsoever. However, you are not doomed to be like that, it is possible for you to bulk up fast and build chest muscles through exercise. However, it is not going to be so easy since you will have to go through more stages to achieve this compared to an ordinary full figured person. You will adopt a good skinny guy workout program that will focus on muscle development rather than burning fat but before you get to that, you have to eat to gain more energy. Anyone can build muscle no matter their physical appearance, they just have to know the right way how.
You have to increase your calorie intake by simply increasing the quality and quantity of food you take. Since you are different from regular guys, you will strive to come close to them by eating more, like six meals in a day but you have to be careful to eat only good foods. This means that there should be no processed carbohydrates, bad fats and junk foods. Increased calories will supply the body with the energy to workout, the body will use proteins and vitamins to produce growth hormones that will be used to build muscle.
Work out your muscles just enough- working out longer does not necessarily mean that you will bulk up more. Your workout sessions should be no more than 45 minutes and you should workout three days a week, not more. In order to build chest muscle, you will basically be lifting heavy to apply pressure on the muscles but be careful on how you do this. Each lifting should have between 8 and 12 reps, not more not less.