Building strength in the shoulders will give you more strength in your upper body while giving you a much more powerful golf swing. The stronger your shoulders are the more ability you will have to hit the ball farther.
Range of Motion
Body weight exercises will increase strength in the core while not putting on excess mass in the upper body. Also with these body weight exercises, your range of motion is enhanced with the increase in strength.
Having a bad shoulder can be the end to any golfers career and shoulder exercises are a so called "prehab" to avoid injury. Body weight exercises work great for increasing strength and at the same time prevent injury from using heavy weights and putting the body into dangerous positions.
There are many workouts that use body weight to strengthen the shoulders. A few exercises to start with include scapular pushups, pushups, planks, side planks, and external abduction exercises.
It is important to watch out for pains and aches in the shoulders. This could be a sign of strains and arthritis in the shoulders. If you feel that your shoulders need strengthening begin with these exercises, but if pain occurs see a doctor immediately.