Nasty girl not right about a single complaint (10)
I believe the answer is:
laryngitis
'complaint' is the definition.
(laryngitis is a kind of health problem)
'nasty girl not right about a single' is the wordplay.
'not right' indicates an anagram.
'about' indicates putting letters inside.
'a single' becomes 'I' (I as in one).
'nasty'+'girl'='nastygirl'
'nastygirl' anagrammed gives 'laryngits'.
'laryngits' enclosing 'i' is 'LARYNGITIS'.
(Other definitions for laryngitis that I've seen before include "Inflammation of the vocal cords" , "Throat infection" , "Inflammation making it difficult to speak" , "Inflammation of the windpipe" , "Inflammation of part of throat" .)