I had this problem 3-4 years ago.
was told by my dr ( a runner) to not use soft soled shoes, and stretch out the tendon by putting your toes on a wall, heel on floor and stretch, it worked, but then the same season The New York Times came out with a short article on how to stop the pain...I have used this method and recommended it to 3 in laws. It worked for them or at least they told me it did . It is at
https://www.nytimes.com/guides/well/activity/treat-plantar-fasciitis?utm_source=sharetools&utm_medium=email&utm_campaign=website
hope this works for you
tommy t