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 not certain 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' means one lot of letters goes inside another.
'pieces of rag' becomes 'ag' (I can't justify this - if you can you should believe this answer much more).
'chin' going within '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" .)