The function of the Achilles tendon is to help in bending your foot downwards on the ankle, as you are doing when you're pointing your toes. (This movement is referred to as plantar flexion.) This may be a bone spur from arthritis. Furthermore, it may be a Haglund's deformity because https://specialistsphere.com/foot-and-ankle-pain-explained-common-conditions-diagnosis-and-effective-treatments/