Causes and Treatment of Periscapular Bursitis
Periscapular bursitis is a possible cause of upper back pain. The scapula, also called the shoulder blade, is an important bone that shifts its position with the upper body and shoulder movement. The motion of the scapula on the upper back is critical to the normal function of the shoulder and the spine. When movements of the shoulder blade are abnormal, significant inflammation and pain can result.
Source: Verywell Health