Bag pressure - that hurts! (5)
I believe the answer is:
pouch
'bag' is the definition.
(I know that pouch is a more specific form of the action bag)
'pressure that hurts' is the wordplay.
'pressure' becomes 'p' (abbreviation).
'that hurts' becomes 'ouch'.
'p'+'ouch'='POUCH'
(Other definitions for pouch that I've seen before include "Container for tobacco or young" , "Marsupial's baby carrier" , "Kangaroo's pocket" , "Bag" , "joey's home" .)