Without examining your foot I can not say anything for certain. Possibilities include bursitis, achilles tendonitis, partial tear of the achilles tendon, posterior heel spur, Haglund's deformity.
I suggest you see a podiatrist for an evaluation
Posted By Vivian Abrams DPM on March 04, 2006 at 13:51:14:
For treatment of plantar's fasciitis, hyperkeratois, fat pad artophy, metatarsalgia, diabetic foot, heel spurs, foot odor, Mortons neuroma, Calcaneal Apophysitis, Achilles Tendonitis and more.