NL25 AK Should I be willing to stack off here?

[KAT21]

I am just trying to figure out why I barely win anything with AK at best. This is a spot I will normally get it all in against the avg villain.

UTG had 2[img]/images/graemlins/club.gif[/img] 2[img]/images/graemlins/heart.gif[/img] (four of a kind, Deuces) and WON (+$19.75)
Hero had A[img]/images/graemlins/diamond.gif[/img] K[img]/images/graemlins/club.gif[/img] and LOST (-$21.50)