Tiff .. I had plantar facitis a number of years ago and my podiatrist told me I had to wear shoes with greater stability to keep me from putting pressure on the balls of my feet ...
so I hardly ever wear heels, my sneakers are the ones that are labeled extra stability, and I wear Dansko clogs almost exclusively for work
since I made these changes, I hardly ever have much, if any pain ... I would definitely go to a podiatrist if I were you to make sure what it is you have and to be treated properly (not by Dr. Google)
and Sarah ... denim has natural give and stretch ... most people can fit into a smaller size jean than they can in a dress/work pant ... the joys of working as a retail clothing manager is you know stuff like this