It's hard for everyone to gain muscle. If it was easy, everyone would do it! It seems that your #1 problem is that you're simply not eating enough food to gain weight. You need more than just protein, you need to be in a calorie surplus to gain weight and muscle. As an active teen, you're probably going to need over 3000 calories per day to gain weight.
Although protein is essential to gain muscle, more is not always better, you don't need as much as you might think. At your current weight you don't need more than around 60-100 grams of protein per day, anything more will just be converted to glucose by your body and used for energy. High protein foods are also very satiating so if you don't have a big appetite, eating tons of protein is going to make it even more difficult to get the calories that you need. The majority of your food intake should be carbs.
You also need to be doing the right things in the gym to stimulate growth in the first place. You should be following a...
(Continued)...proper strength training program written by an expert with a focus on heavy compound movements with a barbell like squat, deadlift, bench, rows and standing press. All other lifts are of secondary importance and probably optional. Focus on progression on these lifts, add weight when you can. If you're unable to add weight, add reps. Make sure you always use good form to avoid injury. If you're unsure about how to perform these exercises get someone to teach you or do some research, watch YouTube tutorials etc. Learning these lifts is important. I've never met anyone with an impressive physique who isn't also very strong and proficient in at least 3-4 of these lifts, there's a reason for that.