Chronic plantar fascia

Have a look at "Plantar fasciitis" at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3954277/ 

@fatherinpain
 I had plantar.
Did several things wore better shoes- crocs or slippers as example maybe comfy or simple to slip on but not good long term
I eventually found new balance trainers to be very supportive.
I froze a 3/4 filled plastic water bottles (500ml/pint sized) and rolled my feet over them, gradually pushing down you can use a ball too.
and when it was at it worse I made a night splint, not using the new kenisology tape but tubigrip. Google PF taping, just keeping foot in same position helped. Doing that for a few nights alleviated  foot pain. 
I get the odd twinge now and again, and make sure I wear supportive footwear at some point during my day.
hope this helps

Ask for a review. What are the muscles like in the rest of your leg and calf? Could there be something else? How about seeing a chiropractor? I was on a waiting list with this after my first child then a chiropractor cured it by accident when treating something else. Could an overall body review help because pain begets pain.

@fatherinpain
Plantar Fasciitis isn't that dissimilar to any other form of tendonitis, and it boils down to overuse, or improper use, usually a combination of both. (exception here is if there is a bone injury or scar tissue that make the condition a different approach to remedy)

Wearing soft, squishy, "comfortable" shoes is going to make it worse. As with any other tendonitis, rest is important, but unfortunately we have to be on our feet to live our life daily, and that's why things like rolling the bottom of the foot with different objects can help - they create temporary disruptions in the neural feedback to our brains, decreasing pain, and can even help straighten out some the soft tissues that have become wavy, knotted up or damaged over time.

In addition to resting to avoid exacerbating the problem, you need to start practicing walking with as perfect of form as possible. Also, if you are overweight, you'll want to start losing those excess pounds because that is just more stress on all of your connective tissues and that's just making it harder on your body.

To simplify how to walk correctly, start with a shorter gait cycle, landing your feet underneath your body each step, and actually grab the ground with your toes (no matter what shoes you're wearing). Grabbing the ground ensures that your arches are going to be active and the big toes is pressed into the ground, which is directly connected to the glute muscles which need to be activated properly make sure your body's posture is supported correctly. 

I would bet that if you watch yourself walk normally (barefoot), your ankles collapse inward, so does your arch, and your arch is longer than it should be b/c it's not active. This stretches out the fibers running through the foot, stretching them under load, and that's specifically how we stress our muscles when we're trying to increase their size; it creates micro-tears that our muscles can quickly repair, creating larger muscle tissue (both healthier and more attractive). Connective tissue like that running through your feet, however, don't repair nearly as easily as muscle tissue, so these tears go un-repaired day after day, more torn with every day you walk improperly, and it's no surprise pain onsets.

I hope this is helpful, educational, and it starts a new intentionality you can apply to your daily like that in the coming weeks and months should start making small but significant improvements in your condition(s)!