Tips for shoes and foot pain

26F here, not formally diagnosed but seem to have developed PF on a DC trip about 1.5 years ago (tons of walking). It was excruciating and nearly ruined my trip. It took about a full week for it to feel better (the Strassburg sock helped a lot), but my foot hasn’t been the same. I bought some PF insoles while on my trip and it made it semi-bearable and I still have them.

I wear very flat Doc Martens to work and Vans/Sambas everywhere else. I do normally wear some 10 year old Nike Free Runs to walk on my treadmill, but figured it might be time to upgrade.

I got some Nike Pegasus 39s and they seem to be making my feet way worse. My left foot usually got irritated, but now my right hurts more since wearing the new shoes. I even put my PF insoles in there and it’s better, but they still hurt. About 15 minutes into walking I get a pain in my foot that feels like it needs to pop or crack but it never does.

Does anyone have any tips? Do I need a zero drop shoe? Are the 39s a bad model?

Ramping up my walking to lose a few pounds and my feet are really hurting. Thanks :)