For me, I had it in my right foot and actually ran a half-marathon with it. Here's how I managed:
I stretched it regularly. All the time, really. Soaked it daily in an epsom salts bath (no idea how primal any of this is, just what worked for me). Took antinflammatories daily until the pain was manageable. And I got the best possible shoe inserts you can buy (as it worked out, they are really cheap and handmade by a local guy.) They made my life livable. And now, I have no issues. Once I healed, I worked on wearing LESS shoe when possible. I still wear really cushioned sneakers, but when I'm not working out or running, I go barefoot or with minimal support. I think that has helped strengthen those muscles. Eventually, I'd like to transition to a minimalist sneaker, but for now, this is what works.
See if you can find someone who knows a lot about the structure of feet. Not necessarily an podiatrist, as they are full of CW. I found a really great guy from Vietnam, English is sketchy at best, but he gets feet. He gets high quality leather insoles and cuts them to match the contours of your foot. It's amazing, and they last for years.