He was walking with the bag slung over his right shoulder.
このジャケットは右肩のところがほつれている。
This jacket is frayed at the right shoulder.
I hurt my right shoulder during baseball practice.
右肩 refers to the right shoulder, while 左肩 refers to the left shoulder, the opposite side of the body.
Compound of 右 (みぎ, 'right') and 肩 (かた, 'shoulder').