I am not able to breath deep. Help!

From last 5 months i am not able to breath deeply i was diagnosed with h pylori ,ulcer and gastritis and i have been on ppi and other medecines for more than 3 months the problem is i feel tightness in stomach and i am not able to pass the gas even though i exercise and eat proper diet ,i always feel like food is filled till my throat and i have visited alot of doctors of gastro and chests physician no one is able to diagnose my problem one more thing when i try to burp i feel alot of pressure in my stomach and always feel bloated been on every type of medecines prescribed by gastros acid reflux was there but still after 5 months of treatment i am not able to breath deeply it feels chest heaviness and while exercise i feel hunger for oxygen please help