Hi I Have Been Suffering From Chest Tightness During Extortion.

Hi
I have been suffering from chest tightness during extortion. However, it does not happen all the time. I have gone through the investigation like ECG, Electrocardiography, ETT and Ultrasonography. I also did some of the pathological and biochemistry test. All the result are;
ETT, ECG and ECHO are fine. In Ultrasonograpgy it detected that my level get enlarged mildly and it get fatty at grade-ii stage. In addition, my cholesterol level get higher. I have been suffering from hypertention since last ten years and I intake medication for this regularly. I do not have problem with diabetes. I am now at 49 my weight is about 78kgs and height is 156 cms. I have consulted with a doctor and he told me that I do not have any problem with my heart. But he could not confirm me why me chest get tight during extortion and it is not happening all the times. Just to give you further information, sometimes I also felt discomfort in the upper belly under the chest and also feeling a tendency of vomiting. This happens during the morning. I am a smoker and puff about 4/5 cigarette day on an average. Could you please explain why I have been feeling like this and what should I do.