Hi , i ve been running regularly and one night after i came home from running , my heel was hurting, 3 days later , it s still hurting. It s like a small circle patch on my heal that is swelled and i can see a black spot inside. It doesnt hurt when i m relaxing or sitting down but when i put pressure on it , it causes pain and now causing me to limp when walking. I am training to run a half marathon and worried this could halt my progress , what is it and what should i do? Thanks AAAAAA