About 15 years ago when I was in my middle 40's, I developed a bad case of PF in both feet. This was right after we joined the tennis club and I started consistently playing for the first time in more than twenty years. I went to a couple of podiatrists who recommended the standard stretching/massaging and inserts, which marginally helped. My PF was so bad it would take me upwards of 30 minutes to get up, walk 20 feet to grab a shower and shave, and another 30 minutes to walk two blocks to a bus stop.
A sports medicine doctor at the Club noticed my limping around and told me to try using a couple of those foam inserts that ladies use for the balls of their feet in high heels. I was so desperate I stacked two or three of them together on each side. It hurt like a mutha from so much pressure on my arch but I was determined to see it through. Every day, the same hour of pain to get to the bus stop. Until about two weeks later when I suddenly noticed the symptoms getting better. Two more weeks and I was walking and playing tennis pain free for the first time in months.
Since then, in every pair of athletic shoes I use, I put a stack of three of those foam inserts under the arch and have not had a recurrence of PF since. Worth a try if nothing else has provided relief.