Shoulder and arm pain can be due to over use, trauma, or arthritis, but often it arises from nerve impingement in the neck.  Nerves that make the shoulder and arm work come from the brain, and exit the lower part of the neck travelling to the shoulder, down the arm, and through the wrist to the fingers.  There are about 15 muscles that make the shoulder function.  All the muscles of the shoulders must be tested to determine what isn't functioning properly.  There can be chronic weakness of a specific muscle of the shoulder for a long time and, when a new stress arises, we think the problem just developed.  If painting, digging, or a new exercise program suddenly makes your shoulder start to hurt it could have easily been a latent weakness in one of the 15 muscles that make up shoulder biomechanics.  That is why Dr. Ehle will individually test each muscle to find the source of the malfunction in the shoulder.  He will then diagnose the reason the specific muscles are not working like they should.  The problem is often a pinched nerve in the neck or upper back.  Other issues could be an acupuncture meridian that is out of balance, organ weakness (liver/gall bladder problems often express as shoulder problems), nutritional deficiencies, or trigger points within muscles.  Deeper problems can be a labial and/or muscle tear, or arthritis which may require x-ray, ultrasound, or MRI imaging.