Thanks for your query
Feeling an air bubble trapped right under your sternum indicates that you have shortness of breath
. You also have chest pain and chest tightness
. There may be many respiratory and cardiac causes for your symptoms. Asthma may sometimes present like this. Ischemic heart diseases may have similar presentation though it is very rare in your age group without any comorbidity. Better to consult a pulmonologist
and get yourself locally examined and go for the following investigations -
1. ECG in 12 leads
2. Pulmonary function test
3. Echocardiographic examination.
Another non-respiratory non-cardiac cause of your symptoms may be gastro-esophageal reflux disease (GERD) which may present similarly. You should have pantoprazole
tablet before food along with domperidone
or itopride for 1 month to lokk for symptomatic improvement along with 3-4 litre water/day. I think by all these you will get the answer.