MyTPI.com by Michael Carroll
Injuries in amateur golf are very common. Each year between 15-41% of amateur golfers report an injury. 31-90% of professional golfers report an injury annually. Professional numbers are higher due to their much higher practice and play volumes. The most common site of injury is the lower back accounting for 18-36% of injuries. The elbow, wrist, hand, and shoulder are also common injury areas.
(Numbers vary depending on which studies you read, the ones above are taken from a review of a number of papers).
The vast majority of these issues are overuse in nature.