Some tobacco licensing is a pain (5)
I believe the answer is:
colic
'pain' is the definition.
(colic is a kind of pain)
'some tobacco licensing is a' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'COLIC' is hidden within 'tobacco licensing a'.
(Other definitions for colic that I've seen before include "unpleasant gut feeling" , "Abdominal pain, especially in infants" , "one for babies" , "Inner pain" , "Intestinal pain" .)