Inflammation from the bursa behind the heel known as Retrocalcaneal Bursitis. Repetitive stress or friction in excess of the back of the heel causes the bursa to swell leading to heel pain and tenderness, swelling and ankle stiffness. Often connected with Achilles Tendonitis and Haglunds Deformity.   Plantar fasciitis is noticed https://www.theorthopaedicandpainpractice.com/the-definitive-guide-to-diagnosing-and-treating-ankle-pain-in-singapore/