What lies behind the pain after shoulder dislocation?

A 38-year-old man presented to our emergency room with severe pain and inability mobilize his right shoulder joint after a violent blunt trauma during work. The humeral head was palpable anteriorly, the loss of normal contour deltoid acromion prominent posteriorly laterally, as it occurs in anterior dislocation. easily reduced on 1st attempt using 1.5 mg/kg intravenous fentanyl 0.5 mg/Kg midazolam sedation room. After procedure, he complained at head, so we performed an X-Ray.