Repetitive motions, lifting objects incorrectly, and sudden awkward movements like twisting or pulling a muscle or tendon in the upper back can strain these tissues. A strain can develop suddenly ...

The continual strain on your neck, shoulder and upper back muscles causes these muscles to tear (on a microscopic level). Your body tries to prevent this tearing by forcing these muscles to knot up.

Coat hanger pain affects the upper back, shoulders ... postural instability (gait and balance problems) can strain the neck and shoulder muscles, leading to muscle tension and pain.