Acidity is probably due to improper diet after recovery. Eat good nutritious food and if you still feel symptoms you can take medication.
Post COVID many sequelae are being seen. Monitor your SpO2 regularly, before and after exercise, if possible. Do proning, minimum 2 and maximum 14 hours per day.
You can take an HRCT and show it to a doctor. If there is residual lung fibrosis, some medicines are available to treat that.
Next Steps
take care of Nutrition, Monitoring and Proning