Hi... I am a 52 year old female, 5' 10", 180 lbs. with no health issues except that my left back of heel start hurting . When I push on the back of my heel, it hurts. The skin almost feels like it hurts to the touch. When I press on the bone at the back of my heel, it its sensitive. When I first get out of bed and my feet hit the floor, the left foot hurts to walk but then doesn't bother me as much after awhile. What is this? Thank you, MA