Sensitive therapy ends stifling shout of pain (6)
I believe the answer is:
touchy
'sensitive' is the definition.
(I've seen this before)
'therapy ends stifling shout of pain' is the wordplay.
'ends' means to remove the middle letters.
'stifling' is an insertion indicator.
'shout of pain' becomes 'ouch' (I've seen this before).
'therapy' with its middle removed is 'ty'.
'ty' enclosing 'ouch' is 'TOUCHY'.
(Other definitions for touchy that I've seen before include "Ticklish" , "Quick-tempered" , "sensitive" , "Quick to take offence" , "Easily offended in tactile way?" .)