I have them on both heels. My foot doctor sent me to physical therapy with a perscription for cortisone liquid. They gave me a lot of different exercises to stretch my foot..then afterwards..put the cortisone on an electric device and infused it into the heels. I went 3 times a week for over a month. At one point the doctor had my one foot in a cast. They don't hurt now..but I still feel a twinge.
I hope you get some relief. Good supportive sandals really help. Birkenstocks are good and sketchers raggae sandles. I can't wear a shoe with an enclosed heel anymore.
I would see a podiatrist also..Best wishes.
Peace and blessings