Examination of pain in the neck (5)
I believe the answer is:
trial
This clue is a double definition.
'examination' is the first definition.
(I've seen this in another clue)
'pain in the neck' is the second definition.
(I've seen this before)
'of' is the link.
(Other definitions for trial that I've seen before include "Hearing - test" , "Annoyance" , "Experiment - adversity" , "Legal hearing" , "Court proceeding" .)