Foot pain on track, not on concrete. Eh?

[Isaac]

Dear Dr. DBB,
So when I run on my school track these days, which is made of this soft material, I seem to have a bit of pain building on the back bottom part of my foot. Using the same shoe, on concrete, I ran outside on this running path, installed by the city. It was over 3 miles and I could have done 5. No pain. Felt great. I was like a missile with legs. Any idea why?

[fliptw]

you might have a nerve thats getting pinched.

[sdfgeoff]

for me it's the opposite!

More than 15 minutes running on concrete and things start hurting, but on grass sidewalks, or parks (grass/dirt = softer) then it's fine.
Go figure...

[Duper]

Where specifically is the pain? The bottom of the foot is a crowded place.

What KIND of pain? Describe it, where does it go?

What shoe are you using and how old is it?

[Isaac]

Actually, I'm wondering if the pain is just gone.

As for the shoes question, they're new. Maybe they just needed some breaking in, or whatever. They're fine now, I guess.