Hello, I'm a 14 year old male teen looking to gain some muscle. I'm about 5'7 and weigh 123 pounds. I have very flabby skin so I'm trying to tone myself up. I've tried to do push ups to help work on my chest. To focus more on my chest I've put my hands more apart. When I do them slowly it's much more difficult,but when I do them quicker I feel a burning feeling on my arms much more stronger,which i believe is associated with muscle growth. On the other hand, when I do either one, I dont feel much strain on my chest. So, should I do my push ups faster or slower and also am i doing my push ups wrong, which is why i dont feel a strain on my chest?