Mine started with a bruised heel. It seems that karate , 90-120 minutes 3-4 times a week on hard floors can strain a foot some. The PF flared up about year 8, about 3 years ago for me, mostly left foot.
It seems that folks have to work out what works for themselves.
I stretch a lot in the morning, absolutley first thing after waking up (after reading the Bible), stretch that foot before it even touches the floor. I wear Dr. Scholls PF inserts in EVERY pair of shoe and boot I own, even gym shoes which are good New Balance shoes, work boots, motorsickle riding boots you name it. If (when) it flares up, I take a small cheap bottled water, freeze it solid, put it in an old sock and roll it under my foot. More than one doctor and deep-tissue massage person has recommended this. Mine is not not nearly so bad nowadays, seems to have peaked and is fading, very slowly.
I also believe that losing weight helps.
HTH a bit, Tommy