Bottom of my feet hurts HELP?

i was runnning other day with a bad pair of running shoes, the shoes are nikey and there made for running but there really old and bad and i was wearing em cause my good nikes were wet so my friend made me run on the track with em and now the bottom of my feet feels like the pain is pushs in it doesnt hurt when im walkin only when im running i have a race and 3 days so please tell me how i can fix it