Sometimes feel difficult to inhale or breath in

Hi, good day to u. I’m 33 y.o., female, non-smoker, non-drinker, just completed 2 doses of COVID-19 vaccines (Pfizer) and tested negative via self test kit. Since 1 month ago (roughly after my 1st dose of vaccine), I sometimes have the difficulty in breathing in air to my lungs. This situation triggers during my sitting and laying posture. Standing posture seldom got the trigger but once it’s triggered, even standing posture not reducing the difficulty. Sometimes I will apply balm near my nose to soothe the situation, sometimes lower room temperature (turn on Aircon) also helps. This situation has been persist till today. Sometimes it doesn’t appear in a day, but sometimes it appears several times a day. Any experts here could provide an advice or give a clue about what happens to me? Thank you so much!