After your shoulder was injured, it has not been able to move around like it normally would. Exercising helps strengthen and rehabilitate the shoulder. After using these strengthening exercises for a while, you will begin to notice an increased amount of mobility and strength. But first and foremost need to stress safety.
Shoulder Exercise Safety
It is bad enough that you are suffering from a shoulder injury. But you must not make your shoulder injury worse worse by not using some common sense. Exercising too soon after your shoulder injury occurred may actually be damaging. Wait at least two days after your injury occurred before starting any exercises and seek medical advice before starting to exercise the shoulder.