Inflammation on the Achilles tendon (Achilles tendinopathy) could potentially cause pain in the back of the ankle, going down on the back on the heel. Botulinum toxin (as in Botox and other makes). This treatment utilizes a protein made by the bacterium Clostridium botulinum Roll the arch of your foot https://specialistsphere.com/foot-and-ankle-pain-explained-common-conditions-diagnosis-and-effective-treatments/