what's your achilles heel?

My heel is killing me! I joined a gym to have access to the elliptical machines, they are PERFECT for my (lame) feet! Low impact with the cardio workout of a run. Today I threw caution to the wind and hopped on the treadmill (even though it was beautiful outside...I wanted a steady terrain for running), the workout was FANTASTIC and I was LOVING running again...even on a treadmill! BUT I am feeling it now. My feet are throbbing and my right heel is VERY tender. Looks like I have ice and stretching in my future...better get to it!