What Could Be Causing My Chest Pain And Abnormal ECG Results Given My Family History Of CAD??

I have been having chest pain on and off for about 1 year. ECG is always abnormal with inverted T wave in V3 and now also in V4,V5 and moderate mid precordial repolarization disturbance. I have done many other test and they are normal. CT angio showed no blockages, blood pressure, cholesterol is normal, I take a medication to slow down my heart rate due to sinusal tachycardia. What else could it be. I should add im only 30 years old and my dad has severe CAD with 14 stents and 4xcabg.