Sons suffering in Catholic country (5)
I believe the answer is:
spain
'catholic country' is the definition.
(Spain is a majority Catholic country)
'sons suffering' is the wordplay.
'sons' becomes 's'.
'suffering' becomes 'pain' (suffering is pain).
's'+'pain'='SPAIN'
'in' acts as a link.
(Other definitions for spain that I've seen before include "Crazy pains?" , "Kingdom" , "EU country" , "country of mostly dry mountains, going by air" , "Country bordering Andorra" .)