Inflammation with the bursa powering the heel is known as Retrocalcaneal Bursitis. Repetitive stress or friction in excess of the again in the heel brings about the bursa to swell leading to heel pain and tenderness, swelling and ankle stiffness. Generally affiliated with Achilles Tendonitis and Haglunds Deformity.   Plantar fasciitis https://www.theorthopaedicandpainpractice.com/the-definitive-guide-to-diagnosing-and-treating-ankle-pain-in-singapore/