dying at a young age
殤 centers on the tragedy of a life cut short: dying at a young age, before one's time.
殤 combines 歹 (death) with a phonetic element that also suggests injury or harm, together expressing premature death.
The left side 歹 means death, and the right side looks like a broken body. Picture a young life cut short, marked by the death radical.
For ショウ, imagine a short, sad show about a young life ending too soon: show -> ショウ, and the tragedy unfolds on stage.