Protein. Your muscles require protein to heal itself after intense exercise. In general, your body requires 1-2 grams of protein per kilogram gram weight. For muscle growth, you would need more. For maintenance, you would need less. You can get enough protein from your diet (lean meats, nuts, etc) or, if necessary, supplement with protein shakes. And don't forgot to hydrate with lots of water.
Agree with exception. 1.2-1.8 grams/kilogram, in my opinion, is the correct amount of protein intake per day during periods of muscle building. 1-2 grams/pound could be considered excessive and adverse effects are possible.
Muscle Growth. Protein is the key to increasing muscle mass. You need 1-2 grams per pound to grow muscle. That is more then most people can consume in just a diet. Lean meats such as chicken, turkey as well as lots of fish. Soy has lots of protein. Check the protein shake and make sure it is low on carbs or no carbs. Isopure products taste great and they come in both low and no carbs.