I think I have an answer to the sharp, shooting, stabbing pain which I was experiencing up to 8 or 9 times a day. Sometimes it was so painful that I would scream out in pain. It vanished as quickly as it came. Then one day I decided to steam vac all the rugs in my house. The steam vac equipment is heavy and required that I push and pull the machine with a fair amount of strength. It took me a couple of hours do clean all of my rugs. Later that day I noticed that I wasn't experiencing shooting pains in my heel. That night I had one mild pain. Then next day I experienced a couple of mild stabs. Within a couple of days the pain had vanished completely. The only explanation I have for this is that I must have had a pinched nerve in my spine which must have been released while I was pushing and pulling the steam machine. This was a couple of months ago and I have not had a single attack since then. I cannot tell you how relieved I am to not be going through that extreme pain any longer. It is Dec 2017 and I am one very happy person now.