Doctor's Notes on Rotator Cuff Injury
The rotator cuff is a group of four tendons that stabilize the shoulder joint. The tendons connect to the four muscles that move the shoulder in various directions: the subscapularis muscle, the supraspinatus muscle, the infraspinatus muscle, and the teres minor muscle. An injury to the rotator cuff is a very common cause of shoulder pain and can be caused by an acute injury or from repetitive strain. There may be partial or complete tearing of the tendons.
Symptoms and signs of rotator cuff injury include pain in the shoulder and upper arm that can be severe. The pain may be felt at night or when moving the arm in certain ways. If the injury is due to repeated small traumas over time, the pain may start as mild and may worsen over time. If the injury is sudden (acute) the pain may come on suddenly and be intense. Associated symptoms can include a cracking sound when moving the shoulder.
Pain : Test Your IQ of Pain Quiz

Medically speaking, the term "myalgia" refers to what type of pain?
See AnswerREFERENCE:
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.