Man that sucks. I've had some foot issues that nobody could figure out either but I actually solved a lot of them on my own.
When I was in my very late 30's we were building a new facility and we were doing a lot of climbing up stairs, hundreds of steps up an down every day. I started to develop an excoriating case of plantar fasciitis, to the point that every time I got up my feet would have intense, acute pain.
I tried the creams, the heel spur surgery, the ice logs, stretching, everything. I tried the inserts. I tried pain relievers.
I finally had heel spur surgery, worst mistake I ever made. Took a long time to heal, worse pain the the PF, would never had done this had I known.
Finally, after somewhat recovering from the surgery, I got back into the field but not near as limber. Now I had to walk slowly, up and down the stairs. What I discovered is that when I was climbing the stairs, I wasn't letting my foot go completely down to the heel. I was stepping up on my toes, and almost but not quite letting my heels touch the ground fully. It makes climbing stairs that much faster. But what I was doing was stretching the shit out of my tendon on the bottom of my foot.
Once I started climbing flat footed and taking it slower, pain nearly almost all went away.
The second thing I started doing was wearing a much beefier work shoe with a full ankle support instead of stupid low top type shoes. The extra ankle support greatly helped as well.
