Conservative with pain finding hidden store (5)
I believe the answer is:
cache
'hidden store' is the definition.
(I've seen this before)
'conservative with pain' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'with' means one lot of letters go next to another.
'pain' becomes 'ache' (ache is a kind of pain).
'c'+'ache'='CACHE'
'finding' acts as a link.
(Other definitions for cache that I've seen before include "Conceal" , "Something hidden" , "Collection of hidden things" , "Secret source" , "Hiding-place for treasure or stores" .)