What I've learned from my ongoing plantar fasciitis journey. The hamstrings from most people are too tight due to things like sitting at work for example. This can cause pain in knees, ankles, buttcheeks, in the groin area or in the achilles area and said plantar fasciitis. Maybe that could be a cause for you pals.
I have pain in all of these areas and some hamstring stretches and some yoga poses help a lot on most days.
Sorry I don't want to come across as Mister know it all, it's just something I learned the last months. Maybe it can help someone.