Pain somewhere in the mountains with one getting cold (5)
I believe the answer is:
colic
'pain' is the definition.
(colic is a kind of pain)
'somewhere in the mountains with one getting cold' is the wordplay.
'somewhere in the mountains' becomes 'col' (term for a mountain pass).
'with' says to put letters next to each other.
'one' becomes 'i' (roman numeral).
'getting' says to put letters next to each other.
'cold' becomes 'c' (eg on taps).
'col'+'i'+'c'='COLIC'
(Other definitions for colic that I've seen before include "suffering" , "Gripe" , "Acute abdominal pain" , "Inner pain" , "gut reaction" .)