Listener finding a revolutionary a pain (7)
I believe the answer is:
earache
'a pain' is the definition.
(I know that earache is a type of pain)
'listener finding a revolutionary' is the wordplay.
'listener' becomes 'ear' (body part which hears or listens).
'finding' is a charade indicator (letters next to each other).
'revolutionary' becomes 'Che' (Che Guevara).
'ear'+'a'+'che'='EARACHE'
(Other definitions for earache that I've seen before include "Lughole pain" , "Aural discomfort" , "pain (from hairdryer treatment?)" , "Incessant complaining" , "Form of torture" .)