Inflammation of the bursa behind the heel is referred to as Retrocalcaneal Bursitis. Repetitive stress or friction in excess of the back on the heel triggers the bursa to swell leading to heel pain and tenderness, swelling and ankle stiffness. Typically related to Achilles Tendonitis and Haglunds Deformity.   Overall health's https://www.theorthopaedicandpainpractice.com/the-definitive-guide-to-diagnosing-and-treating-ankle-pain-in-singapore/