Golfer's need two things to create a proper pain free golf swing:

1. Mobility - Mobility is the combination of muscle flexibility and joint range of motion.
2. Stability - The ability to control the motion of a joint.  

The body is an alternating pattern or stable segments and mobile joints.  If there is a limitation in the mobility of a mobile joint the stable joint above and below will compensate to create movement and a stable segment will become mobile.  When this pattern is affected, this is how golf related injuries and poor swing mechanics can develop.  In the picture of Camilo below to create a proper coil into the backswing the following is needed:

1. Trail hip mobility
2. Thoracic mobility (upper back mobility)
3. Shoulder mobility
   
4. Wrist mobility
   

If there is a limitation in the thoracic spine for example, to create a backswing you will rely on

• a stable joint such as the lower back to move which can create injury
  
• a swing compensation such as a loss of posture to create a full backswing.