Sir,i'm asking this question for my friend... He is 28yrs old 5'11'' and had undergone a coronary-bypass-surgery two years back.. But since the last few months he is experiencing a sort of excruriating pain in his chest,as though someone s punching him hard at d site o his operation. It also radiates to his left shoulder and the jaw.This pain gets aggravated when he s in some emotional stress or in case of physical exertion...and if he tries to control the pain,he'l be going out of breath too..this is getting worse by the day.please tell me why this is happening,and to what is to be done.