I have breathing problem, my nose is often blocked and as a consequence of breathing from my mouth, sometimes i feel that my chest aches and i have not taken a proper breath in ages, and it suffocates.It does not happen all the time, just once or twice a month. I have been to lungs specialist, etc, one doctor prescribed it as just anxiety (but it does not always happen when i take stress or get agitated) and another doctor said it’s allergy.What are the tests that I should go through to be sure?