I have plantar fasciitis and it came on all of a sudden in pretty much the same area you described, left side of heel
of right foot. It is now on my left heel
, in right side of heel
. Have you been on your feet more recently? Increased your exercise? Mine came on after increasing exercise. Currently, I am stretching it at least once per day, doing some strengthening exercises 2-3 times per week. I also apply ice 1 time per day for about 15 minutes when I need to.