Pine store's not opened (4)
I believe the answer is:
ache
'pine' is the definition.
(I've seen this before)
'store's not opened' is the wordplay.
'store' becomes 'cache' (cache is a kind of store).
'not opened' means to remove the first letter.
'cache' with its initial letter taken away is 'ACHE'.
(Other definitions for ache that I've seen before include "Hurt; yearn" , "Feel sore" , "agony" , "strong feeling" , "Shakespearean character" .)