Headache? Me, I ring a doctor (8)
I believe the answer is:
migraine
'headache?' is the definition.
(migraine is a kind of headache)
'me i ring a doctor' is the wordplay.
'doctor' indicates anagramming the letters.
'me'+'i'+'ring'+'a'='meiringa'
'meiringa' anagrammed gives 'MIGRAINE'.
(Other definitions for migraine that I've seen before include "attack" , "Intense headache" , "Crippling headache" , "Recurrent throbbing headache" , "problem for the head" .)