Listener treated each pain (7)
I believe the answer is:
earache
'pain' is the definition.
(I know that earache is a type of pain)
'listener treated each' is the wordplay.
'listener' becomes 'ear' (body part which hears or listens).
'treated' indicates an anagram.
'each' is an anagram of 'ache'.
'ear'+'ache'='EARACHE'
(Other definitions for earache that I've seen before include "Pain inside the head" , "a problem for some listeners" , "listener's discomfort" , "otitis" , "Aural complaint" .)