• it's really important to do a breathing test with a pulmonologist to see how impaired the breathing function is. Without knowing the cause, it becomes harder to treat it for longer term

Other simpler ideas in the meanwhile:

• Jal Neti to clean and open up nasal passages if they are constricted. Watch YouTube video to see instructions. This was real helpful to me. https://www.amazon.com/SinuCleanse-Irrigation-congestion-allergies-All-Natural/dp/B000TFR6MG

• Try Nasal dilators for same purpose, along with Jalneti. https://www.amazon.com/Rhinomed-Solution-Reduction-Comfortable-Assorted/dp/B011LR55UU

• Some light steaming to open up passages

• Nasal inhalers like https://www.amazon.com/Vicks-Inhaler-Breather-0-5ML-Tubes-6/dp/B00FX4FSGO/

• Alternate nose breathing to improve oxygenation capacity. But this can be done only when you're able to get past the current discomfort. https://youtu.be/TKNITh99roA

• Magnesium Calm supplement for anxiety and relaxation. Available on amazon too and a very popular supplement.