Thoughts appreciated, please excuse long post! Zero drop wearer, possible too rapid transition couple of years ago set off chronic Plantar Fasciitis (suspect asymmetric Altra heel foam compression may have affected pronation). Now several years of chronic unilateral heel pain. Regular exercises + physio and advice on here (thanks Odd Man) have helped, but the biggest improvement has come with barefoot running on grass - no pain while running, obviously much more of a forefoot gait.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9741467/
I still get Plantar F type heel pain walking distances in my selection of zero drop shoes and boots which I always use an orthortic in. The orthotic is firmish foam with arch support and cushioned heel cup. Tried a few similar types. A week ago I was feeling fed up as I'm due to do a multi day walk starting next week and was preparing to put up with the pain. Set me thinking that if I can run barefoot without pain why don't I remove the orthotic and make my footwear as minimalist and as close to barefoot as possible while acknowledging running and walking biomechanics are different. Surprisingly the pain reduced. But still some. Then I noted that footwear with an intrinsic heel cup like shape, as in my Freet Mudee 2 (Mudee 1's OK) or just soft foam in the heel area was still causing pain.
Paradoxically the most pain free option is a firm flat inside heel area as in my Xero's and Vivo's. Trying to work out why a curved heel cup +/- foam should cause pain? Is there some kind of compressive effect from the cup and does the base of the heel actually want to be flat when loaded to distribute force more evenly? Guess this may just be a problem particular to me, but for now I am glad I have ditched the orthotics and heel cup/foam. Now planning to walk in my Xero Mesa 2's but wonder how my forefoot/metatarsals will respond to the lack of padding!