hi everyone, i was at the gym on monday on the treadmil, and it got into around 4 and a half mins and the heel of my left foot started hurting but i ignored it and thought it would go away, but it got worse when i got to 10 minz on the machine so i came off. i was thinkin if it was the shoes im wearing because i normaly wear trainers with like big heals and air bubbles. and for the gym i recently started wearing sort of flat trainers, i thought it may of been that but any feedback of what could be causing this would be great, thanks.