The dr told me with mine to find good shoe inserts at the grocery and there is a boot that you get from the dr to wear to bed. What worked for me was for a while I would wear shoes that had a slight heal on them. That way I took all the pressure off the heal area. I also found a good natural remedie at the health store to help with pain in that area instead of taking something by mouth.
Plantar fasciitis. It's a tightening and inflammation of the fascia, which is the tendinous structure that runs the length of your foot on the bottom.
There are some things you can do to alleviate the pain - anti-inflammatories usually help, calf stretching can help. Make sure your workout shoes are not worn down, and don't go barefoot around the house - always wear good shoes around to support your feet.
It's a common complaint that it's worse in the mornings and gets better as you walk around on it. That's a classic symptom of plantar fasciitis.
Sometimes these things go away by themselves, but they can also be recalcitrant to treatment, so hang in there. I had it off and on in my 20s while I was doing a lot of running, but it just up and disappeared in my 30s, for no reason.
You can google "plantar fasciitis" for more information and treatments.