Record time inside, being so confined (5)
I believe the answer is:
caged
'so confined' is the definition.
(confined in a cage)
'record time inside' is the wordplay.
'record' becomes 'CD' (compact disc).
'time' becomes 'age' (an age is a period of time).
'inside' is an insertion indicator.
'cd' enclosing 'age' is 'CAGED'.
'being' is the link.
(Other definitions for caged that I've seen before include "in prison" , "Confined behind bars" , "In a zoo?" , "Shut up" , "Cooped up" .)