Inflammation with the bursa at the rear of the heel is called Retrocalcaneal Bursitis. Repetitive pressure or friction more than the back again from the heel leads to the bursa to swell causing heel pain and tenderness, swelling and ankle stiffness. Normally linked to Achilles Tendonitis and Haglunds Deformity.   Plantar https://www.theorthopaedicandpainpractice.com/the-definitive-guide-to-diagnosing-and-treating-ankle-pain-in-singapore/