Thats a really tough call, on one hand they might pack out and get comfy, on the other they might just not be the right fit and taking them to the hill might mean you can not exchange them.
Personally I would bring them back if they hurt just laced up in your living room. My boots feel fine when I'm just wearing them but it's another story when I'm riding. My feet are not happy after a few hours out, and last time after a 5 hour day I could barely walk.
Since yours hurt just laced up imagine the agony you will feel trying to break those bad boys in.