Sharp, stinging pain (5)
I believe the answer is:
smart
I believe this clue is a double definition.
'sharp' is the first definition.
(similar in meaning)
'stinging pain' is the second definition.
(I've seen this in another clue)
(Other definitions for smart that I've seen before include "fly" , "Chic; sting" , "Intelligent; clean, tidy" , "Spruce; sting" , "Upmarket" .)