Proximal plantar fasciitis (PPF) is a newer term to describe one of the more common causes of pain on the bottom of the heel. This condition is believed to be from degeneration and inflammation of the soft tissues in the bottom of the heel where the plantar fascia attaches to the heel bone (calcaneus). With PPF, there's usually tenderness in this area. The pain worsens when getting up and walking right after resting or sleeping. The problem can start after an acute injury to the heel, or it can begin gradually. It can come on after starting a new activity or wearing a new pair of shoes. It can also come from training errors in runners, and from weight gain or obesity.