I too am in the foot pain club. My pain seems to be confined to toe side and in the ball of my foot. I just had my first run out with custom footbeds, and they most certainly did not solve the problem. I already know that I have semi-flat feet, and apparently "long" arches. As in, the length of my arch is consistent with a foot size that is a size larger than my feet actually are. In any case, the custom footbeds should resolve that...maybe they improved something but there is still something going on that is far worse.
I visited a podiatrist and he didn't seem helpful. Just wanted to sell me expensive orthotics.
It's actually pretty funny for me to see people say that they could barely finish a run without pain, because if I got anywhere near a single run complete without stopping I'd be thrilled at this point. I have to rest them constantly.
The mountain I went to had a lot of runs that required lengthy toe-side traversing for goofy riders, which was quite agonizing.
It seems like the next things to try are bindings and boots. I know I can rent boots, not sure about bindings, but I'll ask the local shops.
Oddly, the foot that hurt the most (rear foot) - and still is very sore the day after - felt like it was too small for the boot. When trying the boots on normally, this was not the case, and it's never been the case that foot felt "bigger" in a boot than the other. So I'm not sure if it was a fitment issue, or if it was another issue that then caused swelling, which then made fitment a secondary issue once the foot was swollen.
The pain is mainly on the ball of my rear foot, and more to the outside. While riding, there is overall soreness on both feet, but where I feel it the day after is there.
I'll try the stance thing that the poster above me mentioned as well. Especially since the pain seems to be on the outside of the rear foot, perhaps as if it wants to be aimed back a bit. Right now I'm at something like 20/5. I did try duck stance briefly a few years ago and immediately switched back, but I can't remember if that was due to pain or because I felt like I couldn't control my board as well.