The continued discomfort is from the snapping of the Achilles tendon over the bony prominence. Frequently, there is an associated bursitis. I am not an advocate of injecting this area with steroids, although I know other doctors who do so. There is an inherent risk of the Achilles tendon rupturing after injections of cortisone.
Sorry I can't be more help from my end.
Vivian Abrams, DPM