I wear New Balance cross trainers and have used that type for years without a problem. When you say "under armor" do you mean those plastic arch/heel support inserts or something like that built into the shoe?

I generally sleep on my side, but do flip flop around.

Apparently, you're supposed to do this gradual stretch in the morning right when you wake up and before you get out of bed and get moving. If you can be arsed to do it, it's supposed to help a lot
Hehehe, usually there's nothing gradual about my getting out of bed, my full-to-bursting bladder makes sure of that. and lately it's ow ow ow ow followed by the sound of niagara falls

Cortisone shots in the foot *shudder* sound as painful as the plantar fasciitis. Homey ain't playing that except as a last resort.
It appears this is another indication that my body's 50 year warranty has run out, and I'm slipping into 'old man syndrome'. I will see my doctor tomorrow.