At the beginning of every run, it feels like my feet are made of broken glass. They also feel this way when I get out of bed in the morning. It is very painful, but after a few minutes, I'm ok. At night, my lower legs are in a lot of pain---kind of like being stuck by needles from the inside out. Fortunately during runs my biggest issue is that my legs kind of seize up. It's a very odd sensation and my gait gets weird. It's almost like my legs don't remember how to work correctly. But I have noticed that running on grass or gravel helps with this and I can almost always run through it. For a while, my legs had a very heavy sensation and it has taken me months to get to the place I am now--running long distance again. Running is a dear friend to me and I dread the day that I won't be able to do it anymore. Like you, I feel fortunate that my sfn seems mild compared to most.