Diaphragm is the principal muscle of inspiration. Diaphragmatic dysfunction is seen in many conditions including following intubation, lung disease, prolonged ventilation, neuromuscular disease, phrenic nerve injury. The possible mechanisms of diaphragmatic dysfunction in patients with COVID19 are critical illness myopathy, ventilator-induced diaphragm dysfunction, iatrogenic phrenic nerve injury particularly secondary to line placement, post-infectious inflammatory neuropathy of the phrenic nerve, or possibly direct neuromuscular involvement of the SARS- CoV-2 virus given expression of the angiotensin- converting enzyme 2 (ACE2) receptor in the peripheral nervous system and skeletal muscle. The use of diaphragmatic ultrasound has been widely used to assess diaphragmatic function is well known in patients following prolonged mechanical ventilation. Prolonged mechanical ventilation leads to contractile dysfunction of respiratory muscles, in particular the diaphragm, causing a so-called ventilator-induced diaphragm dysfunction. The latter is defined as a loss of diaphragm force-generating capacity specifically related to the use of mechanical ventilation. However, the use of diaphragmatic Ultrasound to assess its function in Long COVID patients has not been noted and is a gap in the work up of these patients. The purpose of this study is to address Diaphragmatic Dysfunctional (DD) breathing seen in patients with Post-Acute Sequelae of COVID-19 (PASC), which results in shortness of breath/chest tightness and subsequent fatigue. Targeting shortness of breath and subsequent fatigue as a central symptom of PASC will alleviate long term sequelae for the patients with PASC. DD will be addressed by a unique intervention of physical therapy. The goal of this prospective randomized clinical study will be to evaluate the comparative treatment effect of DB on markers, specifically fatigue, dyspnea, 6 min walk test, depression/anxiety, and quality of life (QoL).