Lung nodule with cavity

My son, 20 years old, had a CT scan because of thoracic, lumbar and hip pain. The chest CT scan was normal except for a lung nodule was found. it is a 5 mm pleural based with center low density/cavity on the posterior upper segment of the left lower lobe. He also had recently a lumbar MRI without any abnormalities and also a normal lumbar spine xray, except for chest wall asymmetry and scoliosis. It was recommended to do a follow up Chest CT in a year but I am worried because of the nodule cavitation and the pleura location could be a sign of malignancy especially metastasis including from sarcomas that happen at this age bracket. His hip and back pain is intermittent but strong so I am afraid we are missing something. Are the characteristics of this nodule concerning? Should the follow up be done sooner than in a year?