Getting your muscles loose is very important to playing a good golf game

It used to be muscular, and although it could hit the ball far, I could not hit well consistently. My muscles, especially the chest muscles, prevent my golf swing. Now I am much less muscle strength (not skinny), my golf swing is like butter and hit me very well (although not as far). However, I want to put on muscle mass, and again I wonder if there is a way to maintain my current golf swing, while doing so.