As far as back pain following golf, it could be related to inflexibility or to poor swing mechanics. I am a high handicapper, and the problem I'm running into is topping the ball. Topping the ball can be caused by a couple of things. One is an attempt to lift the ball into the air, which is poor swing mechanics. One of the most common causes I have run across is poor ball position in the setup.
Many students play the ball too far forward in their stance.
If the ball is too far forward, the clubhead is on its way up from the apex of the downswing. Try moving the ball back in your stance about two golf ball widths. If this does not help the problem of topping, see your local PGA Professional for help in your specific case. I just started taking golf lessons. I play about one or twice a month.