Miseries of work, being surrounded by endless muddle (5)
I believe the answer is:
mopes
'miseries' is the definition.
(mope can mean a miserable person)
'work being surrounded by endless muddle' is the wordplay.
'work being' becomes 'op' (I can't justify this - if you can you should give a lot more credence to this answer).
'surrounded by' is an insertion indicator.
'endless' means to remove the last letter.
'muddle' becomes 'mess' (synonyms).
'mess' with its final letter taken away is 'mes'.
'op' put within 'mes' is 'MOPES'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for mopes that I've seen before include "Behaves in a depressed or aimless way" , "Isn't happy" , "Hangs around apathetically" , "Feels dejected" , "Broods about poems" .)