It doesn't sound to me like you are anywhere near ready to start sprinting, sorry for being so blunt. Go on some walks, maybe do some very easy and very short jogs, but no need in injuring yourself sprinting right from the get-go. Do some body wieght exercises and learn to listen to your body. It will tell you when it's ready to move on to more challenging exercises. Download Mark's Primal Blueprint Fitnes for some body weight ideas. The most discouraging thing you could do is find yourself out of action for weeks becuase you over worked yourself.
You'll obtain your goals faster by slowly transitioning than going all out from the beginning.