Question category: Rheumatology
A 25 year old female who works as a gym instructor presents with a three week history of severe right shoulder pain. The pain is throbbing in nature and had an acute onset with the pain worst at this time and it has gradually improved. It is exacerbated by any movement of the shoulder. His arm is held in adduction and internal rotation. There is weakness of the deltoid and serratus anterior muscle. There is normal sensation and reflexes are normal. Which of the following is the most likely diagnosis?