400NL - KK preflop against 2 opponents (one shorty)

[skegvegaspoker]

Party Poker No-Limit Hold'em, $ Hero (6 handed) internettexasholdem.com

Hero ($954)
UTG ($326.30)
MP ($220.82)
CO ($783.70)
Button ($400)
SB ($396)

Preflop: Hero is BB with K[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/spade.gif[/img]. SB posts a blind of $2.
UTG calls $4, <font color="#CC3333">MP raises to $16</font>, <font color="#666666">1 fold</font>, <font color="#CC3333">Button raises to $58</font>, <font color="#666666">1 fold</font>, Hero calls $54, UTG folds, MP calls $220.82 (All-In), Button calls $162.82, <font color="#CC3333">Hero raises to $885.28</font>

Wasn't really sure what BTN's flat call meant.

MP = 23/13
BTn = 19/16
My image is probably that I 3-bet a little too much, because I probably do. Would calling preflop and getting it in on a non-A flop be better? Or even folding.

I didn't 4-bet originally as I was sure BTN would fold all worse hands.