Sometimes 1/2 day to a day after a tough workout, when I lean forward, I get a severe cramping in my chest...it feels like a bad muscle cramp in my ribs (just above the sternum on the right hand side). What is my body trying to tell me? and how can I stretch to stop this from happening?
It clearly is a sign that your upper body is not in par with your lower, which means that over time you have become accustomed to work out heavily for your lower body but not the upper body.
The solution to this is very easy. Start focusing on upper body workouts, preferably bench presses (and all its variations) and also incorporate exercises that work your core such as planks, abs and back extensions.
Perform dynamic stretches when possible and start using a foam roller.
Oh and also stay well hydrated, and of course enjoy your workouts!