What Is The Treatment For Lightheadedness And Heart Murmur?

So, at three days old i had transposition of the great vessels. that is the only surgery they have ever preformed on me. I am 15 almost 16 years old now. At the age of 6 or 7 they released me to do anything as far as sports and things like the army go. i am currently playing football at a fullback position. I have recently (for about 2 months or so) been have massive chest pains and lightheadedness. I talked to a cardiologist at my heart camp and he said that it is a possibility that my heart murmur may be expanding. the pain occurs at random times and the pain last longer each time it happens it almost unbearable at some times and others not so much but still enough to slow me down even at times of rest. I have not seeked medical attention yet. Back to football. I for the most part don t feel much pain on the field . maybe because of the adrenaline? I compete in several sports like wresting and track. As a doctor what do you think is happening to me?