Royal (5)
'royal' is the definition.
(I know that royal can be written as regal)
This is all the clue.
(Other definitions for regal that I've seen before include "Royal - 5 down (anag)" , "King's" , "King-like" , "Like a queen?" , "Kingly glare?" .)
(Other definitions for pain that I've seen before include "Sensation of acute discomfort" , "Unpleasant sensation" , "Physical hurt" , "Symptom of hurt or disorder" , "Physical discomfort" .)