In 2012, more than 68,000 cases involving days away from work occurred due to shoulder injuries, according to the National Safety Council chartbook, “Injury Facts.” Shoulder injuries can seriously affect a worker’s life. The Texas Department of Insurance, Division of Workers’ Compensation states that pain is the most common symptom of a shoulder injury, with other symptoms including stiffness, a “locking” sensation, and numbness or tingling down the arm.