The right shoulder (the shoulder on the right side of the body). Often referenced in relation to the dominant arm or carrying items.
彼は利き腕の関係で右肩に負担がかかる。
He puts strain on his right shoulder because it's his dominant arm.
コートを右肩に掛けて歩いた。
I carried my coat on my right shoulder while walking.
右肩の怪我でバドミントンを休んでいる。
I'm sitting out of badminton because of a right shoulder injury.