Hi. I suffered plante fascitis for years. Now I'm totally fine.
Here is how I cured myself:
1. Do not use flat shoes. Go to a shoe repair shop as ask them to put a elevation of 1 inch (2 centimeters) I your heel. Your weight should be transferred to the from part of your feet (toes), if you continue putting the weight of your body on your heel, it might never recover.
2. Do the same for the shoes/sandals that you use at home. One common mistake is fix the street shoes, and continue using flat footwear at home.
3. The most effective pain relief is feet massage by a fisioterapist. You can try it. But obviously this is too expensive to do on a daily basis. So what I did was buying a feet massage robot. There are many avaliable on the market (Amazon for example) and that way you can give yourself massages everyday. I was doing it in the morning and before sleep.
3. Exercise little by little.
Start running as soon as the pain allows. First run one block, if there is no pain the next time try to run 2 blocks and go progressing little by little. Soon you will be able to run many minutes and finally one day you will be just fine.
Never run for too long, because if the pain appears, you might go back to the beginning again, and you will have to start over again.
Hope you get better and if this helps you, please help me to spread these recommendations in other forums . Cheers