I would suggest to get HRCT CHEST DONE.
It's classic case of Covid 19 induced lung fibrosis (pneumonitis induced).
Meanwhile you can Use Incentive inspirometer ,for 5 minutes three times a day
Based on HRCT findings proper dose schedule is advised.
Next Steps
.HRCT CHEST
.INCENTIVE INSPIROMETER
Health Tips
incentive inspirometer
plenty of fluids
tender coconut water
wishing you Healthy and quick recovery