The first reason to x-ray a painful shoulder is if you believe that there has been any injury to the bone such as a fracture.
X-rays do not show up soft tissue such as muscle and tendons but if you have landed on your arm or shoulder then you may have fractured the bone. Having shoulder x-rays done can also help to prove that it is not from a fracture, so helping to diagnose by a process of elimination.
Other forms of radiography such as x-rays with contrast dyes or ultra-sound can also help to show up more information if it is not a bone-related disorder.
If your doctor recommends x-rays to examine your shoulder pain then what he or she wants to look at is the bones of the shoulder and perhaps the joints between these bones.
For further information about Shoulder X-Rays click the link below: