Suffering, wrap one’s jaw in pieces of rag (6)
I believe the answer is:
aching
'suffering wrap one's' is the definition.
'aching' can be an answer for 'suffering' ('ache' can be a synonym of 'suffer'). I am not sure about the 'wrap one's' bit.
'jaw in pieces of rag' is the wordplay.
'jaw' becomes 'chin' (I have seen 'Lower jaw' mean 'chin' so perhaps 'jaw' could also mean 'chin').
'in' means one lot of letters goes inside another.
'pieces of rag' becomes 'ag' (I am not sure about this - if you are sure you should believe this answer much more).
'chin' put inside 'ag' is 'ACHING'.
Can you help me to learn more?
(Other definitions for aching that I've seen before include "Continuously sensitive" , "Hurting" , "Causing discomfort" , "Suffering a dull persistent pain" , "Giving continuous pain" .)