Playing a simple chord, initially without a complaint (9)
I believe the answer is:
eclampsia
'complaint' is the definition.
(eclampsia is a kind of health problem)
'playing a simple chord initially without a' is the wordplay.
'playing' is an anagram indicator.
'initially' suggests taking the first letters.
'without' means one lot of letters goes inside another ('without' can be similar in meaning to 'outside').
The initial letter of 'chord' is 'c'.
'a'+'simple'+'c'='asimplec'
'asimplec' is an anagram of 'eclmpsia'.
'eclmpsia' going around 'a' is 'ECLAMPSIA'.
(Other definitions for eclampsia that I've seen before include "sickness" , "condition of pregnant women" , "expecting trouble?" .)