A single drunk in support group finds relief from pain (9)
I believe the answer is:
analgesia
'relief from pain' is the definition.
'analgesia' can be an answer for 'relief' (I have seen 'Relief of pain ' mean 'analgesia' so perhaps 'relief' could also mean 'analgesia'). I am not sure about the 'from pain' bit.
'a single drunk in support group' is the wordplay.
'drunk' indicates an anagram.
'in' is an insertion indicator.
'support group' becomes 'aa' (Alcoholics Anonymous).
'a'+'single'='asingle'
'asingle' with letters rearranged gives 'nalgesi'.
'nalgesi' placed within 'aa' is 'ANALGESIA'.
'finds' acts as a link.
Can you help me to learn more?
(Other definitions for analgesia that I've seen before include "Absence of pain" , "Inability to feel pain" , "Loss of pain" , "result of medication?" , "painless" .)