Supposedly comfortable, it causes Charlie a cry of pain (5)
I believe the answer is:
couch
'supposedly comfortable it' is the definition.
I can't judge whether this definition defines the answer.
'charlie a cry of pain' is the wordplay.
'charlie' becomes 'C' (phonetic alphabet).
'a cry of pain' becomes 'ouch' (exclamation said when in pain).
'c'+'ouch'='COUCH'
'causes' is the link.
Can you help me to learn more?
(Other definitions for couch that I've seen before include "Grass; reclining seat" , "express" , "Upholstered seat for more than one" , "Long seat; grass" , "something comfortable to sit on" .)