Teenage Attitude

Well my son that I thought was my good son and was not going to start giving me the "teenage attitude" has started giving me the "teenage attitude," all the time. He said it is because I yell at him all the time. I explained to him that I would not yell if he would not continue doing the things that I have asked him not to do. I also explained that yes I am stressed right now and I don't mean to be short with and apologized to him for that but I will not apologize for yelling at him for doing the things that I tell him not to do. This is going to be a long 7 years.