Extreme pain or misery (7)
I believe the answer is:
anguish
I believe this clue is a double definition.
'extreme pain' is the first definition.
(I've seen this before)
'misery' is the second definition.
(I've seen this in another clue)
(Other definitions for anguish that I've seen before include "Extreme misery" , "Great (mental) pain" , "Great suffering" , "Grief" , "Severe pain, may be mental" .)