Mael

probably because you don't work your muscles hard enough. some people are hard gainers to begin with. i don't know how old you are, or how tall you are, but if your 130 lbs, i'm guessing you have an incredibly fast metabolism, so your gonna need to eat a lot more than 3 meals a day and snacks to put on weight. spread your meals out into 5-6 meals, maybe even 5-6 full meals instead of having them be smaller than a normal meal. you'll still be getting more protein than you really need, but you're getting it and all the other nutrients naturally. also, when exercising, to put on muscle, you need to be lifting a weight that is sufficient enough to fatigue your muscles within 10-12 reps. you might want to try actual weight lifting to go along with chinups, pushups, etc.