Do your pedals have a tension adjustment on them (kind of like how you would adjust the tension on a ski binding)?
The tension might be too tight for you to unclip with ease.

I have shimano spd cleats
Shimano SH-11 SPD-SL Cleat
http://www.lickbike.com/productpage.aspx?PART_NUM_SUB='2995-04'


and shimano spd pedals
http://bike-discount.de/bilder/small...al_schwarz.jpg

I unclip easily and effortlessly. I have issues with my right foot due to an urelated-to-cycling tendon injury. I have never had a hotspot with this cleat and pedal combination because the pressure to the foot is spread out over a larger surface area.

I got this set up at my lbs and just provided the links so that you could have a picture of what this pedal/cleat combination looks like. Another reason that I selected this pedal is that I wanted to be able to run a quick errand here and there without putting on my shoes that clip in to the pedals. I can wear any old shoe with these pedals for short trips without clipping in. I love them.

Good luck in your quest!