Did you grease up the threads on your speedplays and clean out some of the gunk from the crankarm's pedal threads? Bike pedals are tight, but it sounded like you needed some extreme measures to get them off. It's possible the LBS just overtorqued them, or it's possible they didn't grease the pedal threads at all.
A little grease and some cleanliness on the installation will make your job a lot easier should you ever need to take your new pedals off.