Breathlessness or difficulty breathing is counted to be a serious COVID-19 symptom, and chances are, for patients who had some level of lung involvement during their COVID-19 infection (a common manifestation of the Delta variant), it can take a while for the respiratory organ to fully heal, and thus, symptoms like breathlessness, chest pain, shortness of breath could continue for a while.
Persistent coughing, a change in the voice could also be experienced if you had heavy inflammation in the upper respiratory tract.
While patients should focus on restoring lung function and not overstress themselves, one must also do breathing exercises and do slow-paced activities for a while, if the symptoms continue to strike. Some might also require oxygen support for a while to recover well. Soothing drinks and concoctions also certainly help.