Headache - suffering a little further down? (4,2,3,4)
I believe the answer is:
pain in the neck
'headache' is the definition.
(I've seen this before)
'suffering a little further down?' is the wordplay.
'suffering' becomes 'pain' (I've seen this before).
'a little further' becomes 'inthe' (I can't justify this - if you can you should believe this answer much more).
'down?' becomes 'neck' (both can mean to finish a drink).
'pain'+'inthe'+'neck'='PAIN IN THE NECK'
Can you help me to learn more?
(Other definitions for pain in the neck that I've seen before include "Annoyance (colloq.)" , "Troublesome person or thing" , "bind" , "Persistently difficult person or thing (caused by a whiplash?)" , "Really annoying person" .)