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' (to ache is to suffer pain). I am unsure of the 'wrap one's' bit.
'jaw in pieces of rag' is the wordplay.
'jaw' becomes 'chin' (I've seen this in other clues).
'in' is an insertion indicator.
'pieces of rag' becomes 'ag' (I am not sure about this - if you are sure you should believe this answer much more).
'chin' inserted 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" .)