Pulmonary actinomycosis is a rare infection that usually needs biopsy confirmation to be diagnosed. They usually present with chest wall mass or with chest pain. Upon investigation, many have worrisome imaging results that usually represent a mass with some periosteal destruction. Patients can fully recover from this infection if the appropriate treatment was not delayed. A 12 years old boy presents to our department with a one month history of chest wall mass and one week of chest pain that showed great improvement after less than two months of antibiotic treatment.