Pectoralis Major Syndrome is a condition characterized by the compression of nerves and blood vessels in the upper chest area, often due to an abnormality in the pectoralis major muscle. This syndrome can lead to symptoms such as pain, numbness, and weakness in the shoulder and arm, affecting daily activities and overall quality of life. The condition is commonly associated with repetitive overhead activities or trauma, which can cause the pectoralis major muscle to become tight or hypertrophied. Diagnosis typically involves a physical examination and imaging studies, while treatment may include physical therapy, stretching exercises, and, in some cases, surgery to relieve the compression.