Trouble opening up in temple (6)
I believe the answer is:
pagoda
'temple' is the definition.
(I know that pagoda is a type of temple)
'trouble opening up' is the wordplay.
'trouble' becomes 'ado' (both can mean bother or commotion).
'opening' becomes 'gap' (gap is a kind of opening).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'ado'+'gap'='adogap'
'adogap' in reverse letter order is 'PAGODA'.
'in' is the link.
(Other definitions for pagoda that I've seen before include "Hindu temple shaped like pyramid" , "Hindu/Buddhist temple" , "temple? Quite the opposite" , "Sacred many-tiered temple" , "Buddhist temple, pyramid-shaped with many tiers" .)