Parsonage-Turner syndrome, a rare condition with a reported overall incidence of 1.64 cases per 100,000 people. PTS is also characterized by associated delayed upper extremity weakness, muscle atrophy, and painless paresthesias, which tend to diminish slowly and resolve gradually; Although most patients report 80% to 90% muscle strength recovery within 2-3 years, more than 70% of patients experience residual paresis and exercise intolerance. As described in the existing bibliography, the patients reported initial pain in the shoulder and weakness after vaccination that, as it worsened, led them to visit the emergency department. Vaccination is a known cause of this syndrome although there is difficulty in early identification, it is often overlooked or misdiagnosed, Possible immune-mediated mechanisms include molecular simulation and bystander activation, which can occur after any infection or vaccination.