In your ear, pain will go quickly (6)
I believe the answer is:
hurtle
'go quickly' is the definition.
'hurtle' can be an answer for 'go' (hurtling is a kind of going). I am not sure about the 'quickly' bit.
'in your ear pain' is the wordplay.
I cannot quite see how this works, but
'pain' could be 'hurt' (synonyms) and 'hurt' is present in the answer.
This explanation may well be incorrect...
'will' acts as a link.
Can you help me to learn more?
(Other definitions for hurtle that I've seen before include "Lacking speed" , "Move fast; rhymes with marine reptile" , "Dash, move at high speed" , "Career (along)" , "Proceed quickly and noisily" .)