After match, get endless sharp pain (6)
I believe the answer is:
twinge
'sharp pain' is the definition.
(I've seen this in another clue)
'after match get endless' is the wordplay.
'after' means one lot of letters go next to another.
'match' becomes 'twin' (synonyms).
'endless' means to remove the last letter.
'get' with its final letter taken away is 'ge'.
'twin' next to 'ge' is 'TWINGE'.
(Other definitions for twinge that I've seen before include "Slight localised pain" , "Sudden darting pain" , "Small, sharp pain" , "Sudden sharp feeling" , "Sharp localised pain" .)