Difficulty leads to jazz singer making a complaint (7)
I believe the answer is:
rubella
'a complaint' is the definition.
(rubella is a kind of health problem)
'difficulty leads to jazz singer' is the wordplay.
'difficulty' becomes 'rub' (rub can mean a difficulty or problem).
'leads to' means one lot of letters go next to another.
'jazz singer' becomes 'ella' (I can't explain this - if you can you should believe this answer much more).
'rub'+'ella'='RUBELLA'
'making' is the link.
Can you help me to learn more?
(Other definitions for rubella that I've seen before include "German measles" , "infection" , "contagious disease" , "complaint" .)