Thanks for your question on Healthcare Magic.
I can understand your concern.
By your history and description, possibility of stress and
anxiety related symptoms is more.
Stress and anxiety can cause feeling of
chest tightness, chest pressure, inability to take deep breath etc.
You are not having allergies and not having
smoking habit, so lung related diseases are less likely.
So better to
consult psychiatrist and get done
counselling sessions.
Try to identify stressor in your life and start working on it's solution.
You may need anxiolytic drugs too. Don't worry, you will be alright. Avoid stress and tension, be relax and calm.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.