Diplomat having a tough time initially with pain (7)
I believe the answer is:
attache
'diplomat' is the definition.
(I know that attache is a type of diplomat)
'a tough time initially with pain' is the wordplay.
'initially' says to take the initial letters.
'with' means one lot of letters go next to another.
'pain' becomes 'ache' (ache is a kind of pain).
The first letters of 'tough time' is 'tt'.
'a'+'tt'+'ache'='ATTACHE'
'having' is the link.
(Other definitions for attache that I've seen before include "Embassy worker" , "ambassador's assistant" , "Embassy employee" , "Briefcase or diplomat" , "One on embassy staff" .)