Welcome to HCM
We understand your concerns
I went through your descriptions. You are victim of sedentery life style which is the story of every young people around the world. You must be having so many reasons for your life style. But need to understand that it is you who will suffer.
It is well known fact that junk and untimely food causes indigestion
and thereby acidity. Acidity creates gas and gas pushes the diaphragm up and resulting in chest tightness
Regular rigorous exercising, timely food habits, avoiding junk food etc contributes equally in healthy living. Learn to include garlic, onion, ginger, cumin seeds and fruits in diet without fail and every day.
Hope this answers your query. Available for further clarifications.