Pressed to massage one region for greatest effect, most masseurs would target the muscles around the shoulders and between the shoulders and the neck. They talk about tension, and 'knots' almost calcified with trapped energy. Chikung practice increases one's awareness of the tense energy lodged in the shoulder muscles and over time dissolves that clamped feeling.
While doing standing practice, one constantly scans the body, finds foci of tension and consciously relaxes every muscle or tense feeling from the head to the soles of the feet. In order to relax my shoulders, I think of a coat on a hanger. It does not shrug its shoulders in recoil. It hangs loose, allowing the full weight of its arms to to pull it down without resistance. At the same time, it stands erect by virtue of the tension between the downward pull of gravity and the upward force transmitted from the hook of the hammer.