The you need to strengthen the muscles in the bottom of your feet so the load is on the muscles, and the plantar fascia ligament can relax and heal. Imagine a bow with one thin string; now lay several beefy muscles over that and contract them so the thin string can go limp.
Try this stretch - it may help. Stand up, face the soft arm of your couch. Bring one leg up PERPENDICULAR TO YOUR HIPS (not out to the side) and rest your heel on the couch arm. KEEP HIPS AND SHOULDERS SQUARE. With toes up, reach out and grab your toes (if you can do it with both hands it's better). Gently straighten your knee, toes up. Relax. Repeat a few times. Now do the same thing, but rotate your leg so the toes point out. Then rotate your leg so your toes point in. KEEP TOES UP. Relax. Walk around your house barefoot on the outside edges of your feet. Sit on the floor with legs straight out, toes up, and curl your toes down toward your heels (contracting the muscles on the bottom of your feet). Do that while just chilling out at home.
First thing in the morning, while in bed, push the heel of one foot into the bottom of the other, massaging it deeply. Do both sides. Stretch your legs gently just like the couch stretch. NOW get out of bed.
I was rid of my plantar fascitis in 3 months doing this. The key is your foot muscles must be strong enough to unload your fascia. Good luck!
FogRunner