Inflammation on the fibrous band of tissue which spans from the bottom on the heel to the ball with the foot as a consequence of an overuse There is often pain inside the Achilles tendon insertion in the calcaneus (heel bone) posteriorly (driving). The Achilles tendon can be thickened (swollen) https://www.theorthopaedicandpainpractice.com/why-does-the-back-of-my-heel-hurt/