Background: The COVID-19 pandemic has significantly impacted the mental health of healthcare professionals, particularly nurses and paramedics. This study investigates the prevalence of Post-Traumatic Stress Disorder (PTSD) and the impact of social ostracism on psychological distress among healthcare workers (HCWs) in Poland, with a focus on exploring the interplay between professional and social factors contributing to their stress. Methods: A cross-sectional survey was conducted between March 2021 and February 2022 with 852 HCWs from four Polish provinces. PTSD symptoms were measured using the PTSD Checklist—Civilian Version (PCL-C), and social ostracism was assessed through a custom-designed questionnaire. Results: Of the participants, 14.1% reported experiencing social ostracism, and 4.9% observed such experiences among colleagues. Those who experienced or witnessed ostracism reported significantly higher PTSD symptoms (p < 0.001). Concerns about personal health and the well-being of older individuals were strongly associated with increased PTSD severity, while concerns for household members were not. Conclusions: Social ostracism exacerbates the psychological burden on healthcare workers, contributing to higher levels of PTSD. This study highlights the need for targeted mental health interventions and support systems, including resilience training and stigma reduction initiatives, to address these challenges. Future research should explore cross-national comparisons and long-term psychological effects among diverse healthcare populations.