i had PF a couple of years ago, to be honest, the best thing i found for it is the scholl insoles!
A good pair of trainers, never walk bare foot, insoles. I also love the birkenstock betula with the footbed, the sole is shaped like the insoles so has a good arch support.
Supportive shoes really are a must, if the sole flexes too much, then each step will keep doing damage to your foot.
I havent read the whole thread, so apologies if someone already explained, but this is whats happening.
The plantar fascii is the ligament that goes from the heel, through the foot arch to your toes. What happens is the ligament tears from the heel.
When you sleep at night, like a sprain, that tearing begins to heal, so when you get up in the morning and go to walk, you're re-tearing that healing tissue.
Its important that EVERY MORNING you spend at least 5 minutes massaging your foot before you get up, warm up that ligament, you want to gently and carefully use your thumb to massage from your heel up the arch towards your toes and back down again, you will feel it ease.
Once you've done that, you want to sit on the edge of the bed, feet on the floor and gently, without standing, lift from flat feet onto your toes a couple of times.
When you feel there is no stiffness, then stand up.
I did this every day, and mixed with either my birkies or my trainers with the insoles in, it was fixed within 8 weeks, and it hasnt returned.
You have to treat it like you have sprained the arch of your foot essentially. baby it, dont force it, massage, ice, support...etc.