I suffered before fr hurtburn,chest tightness and difficulty of swallowing, but they diagnosed i have only gastritis. 3-4 yrs ago with high cholesterol level,,but this past few months until now, i have dizziness for most of the time, shortness of breating

You are young (33): for heart disease, but could have any number of things that could be causing this. Just because nothing was found with your heart 3 years ago doesn't mean that you have no problem now. And the gastritis could be causing this. Clearly you need some symptom relief, and a few more tests and need to keep in touch with a local doctor for when these symptoms and anxieties arise. Don't give up!