To support a revolutionary brings a sort of pain (8)
I believe the answer is:
backache
'a sort of pain' is the definition.
'to support a revolutionary' is the wordplay.
'to support' becomes 'back' (back is a kind of support).
'revolutionary' becomes 'che' (Che Guevara the Marxist revolutionary).
'back'+'a'+'che'='BACKACHE'
'brings' is the link.
(Other definitions for backache that I've seen before include "Eg, lumbar pain" , "Eg, lumbago" , "Spinal pain" , "common complaint" , "Pain in rear of body" .)