I had exact same thing a few years back. After doctors and tests and pills, nothing helped. Until someone noticed that I was walking in my slippers where the part that should cover the heal, was under my heel. There was a thick seam. I did not realize how slowly I got used to walking like this. It bruised internal tissues of my heel. After I replaced the slippers, it took about a month to heal. Feet heal very slow. Anyway, check your footwear for any bumps or lines or seams in the heal area of all your shoes. Actually press hard with your thumb in the area where heel goes. There could be something hard hiding under the surface. If not that, I would recommend gravity foot massaging rock pillow. No matter what you do, give it time because feet heal slower than other body parts. If you have questions, drop me a line. I'll be happy to help.