Hi thanks for contacting health care magic...... Without known etiology treatment cannot be guided... For proper diagnosis physical examination has to be done .... Consult physician or ENT surgeon for that.... Here you are taking mouth breath , so nasal cause might be there ... Nose examination done by rhinoscopy , Look for deviated nasal septum or nasal polyp like condition..... If no nasal cause present than detail investigation done with following...................... 1.Chest x ray 2.Spirometry 3.ECG 4.Blood pressure checking 5.Tread mill(if needed) According to cause your further treatment guided... Let me know you excess stress also can lead such symptoms/... So avoid stressful situations...... Take care ........