The shoulder: the part of the body connecting the torso and the arm; also used metaphorically (e.g., responsibilities on one's shoulders).
重い荷物を長時間持っていたので肩が凝った。
My shoulders are stiff from carrying heavy luggage for a long time.
冬は肩を温めると楽になることが多い。
In winter, warming your shoulders often makes you feel better.
彼はチームをまとめる大きな肩の荷を背負っている。
He bears the heavy responsibility of leading the team.