Caught quietly breaking up sticks, set back (7)
I believe the answer is:
trapped
'caught' is the definition.
(trapping is a kind of catching)
'quietly breaking up sticks set back' is the wordplay.
'quietly' becomes 'p' (musical symbol).
'breaking up' means one lot of letters goes inside another (inserted letters slice into or 'break up' the word).
'sticks set back' becomes 'traped' (I can't justify this - if you can you should believe this answer much more).
'p' put within 'traped' is 'TRAPPED'.
Can you help me to learn more?
(Other definitions for trapped that I've seen before include "in a tight corner" , "Snared" , "Ensnared, cornered" , "Stuck" , "Caught" .)