A revolutionary is a real pain (4)

I believe the answer is:

ache

I'm a little stuck... Click here to teach me more about this clue!

'real pain' is the definition.
'ache' can be an answer for 'pain' (I've seen this before). I'm unsure of the 'real' bit.

'a revolutionary' is the wordplay.
'revolutionary' becomes 'che' (Che Guevara the Marxist revolutionary).
'a'+'che'='ACHE'

'is a' acts as a link.

Can you help me to learn more?

(Other definitions for ache that I've seen before include "Continuous hurt" , "yearning" , "painful" , "suffering" , "Hurt; yearn" .)

I've seen this clue in the Sydney Morning Herald.

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