Hi, I always work playing as a football goalkeeper, and as a ocacional runner, but last three times, I could feel a sharp pain every time my heart pumped, just after the race or the game finished. I normally play at a synthetic football field, so I was wondering what could it be? And if playing in that field, with the sun at it s maximum could be playing a role in my pain? Thanks for your help, and I ll wait for your awnser. ^^