I'm probing sore with end of pointed instrument (8)
I believe the answer is:
dulcimer
'instrument' is the definition.
(dulcimer is a kind of instrument)
'i'm probing sore with end of pointed' is the wordplay.
'probing' means one lot of letters goes inside another (probe can mean to make a hole in).
'sore' becomes 'ulcer' (I've seen this before**).
'with' is a charade indicator (letters next to each other).
'end of' indicates one should take the final letters.
The last letter of 'pointed' is 'd'.
'im' inserted into 'ulcer' is 'ulcimer'.
'ulcimer' put after 'd' is 'DULCIMER'.
(Other definitions for dulcimer that I've seen before include "Hammered instrument" , "Something instrumental" , "Instrument of Xanadu damsel (Coleridge)" , "Old stringed instrument" , "Percussion instrument struck with small hammers" .)