Fed up with the rheumatism? (5,5)
I believe the answer is:
bored stiff
'fed up with the rheumatism?' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'fed up with the rheumatism?' is the wordplay.
'fed up' becomes 'bored' (fed up can mean bored).
'with' is a charade indicator (letters next to each other).
'the rheumatism?' becomes 'stiff' (I can't explain this - if you can you should give a lot more credence to this answer).
'bored'+'stiff'='BORED STIFF'
Can you help me to learn more?
(Other definitions for bored stiff that I've seen before include "Suffering tedium" , "Very fed up" , "Extremely uninterested" .)