Chanter shouldn't be too hard to blow. Most beginners I've taught almost universally over blew the reed to shut off. Your lips should give out before your lungs, but you shouldn't be in pain! Orthodontic elastics on the blade (folded over depending on diameter) should close the lips. As for your wrists, it's almost certainly a result of bending your fingers. Bottom hand should be center pad of ring, middle, and index fingers, center and slightly toward bottom on pinky (low A). Should cause wrists to flatten a bit and avoid cramping. Also, get in the habit of playing with chanter bottom elevated on a table. For some reason crotch players (I'm sure there's a better term) tend to fold in once they're on the pipes.

Unrelated.... Is Mike Katz playing uilleann bellows in that clip? They look huge.