Son in pain? He made sure it was all over! (5)
I believe the answer is:
hurst
'he made sure it was all over' is the definition.
The definition suggests a singular noun which matches the answer.
'son in pain?' is the wordplay.
'son' becomes 's'.
'in' indicates putting letters inside.
'pain?' becomes 'hurt' (hurt is a kind of pain**).
's' going within 'hurt' is 'HURST'.
Can you help me to learn more?
(Other definitions for hurst that I've seen before include "World Cup hero" , "Wooded rise (archaic)" , "Grove" , "wood" , "A few ashes maybe" .)