Complications of rib fractures include pneumothorax, hemothorax, and pulmonary contusion/laceration. Without having access to the actual images, it is not possible to determine if you have a pulmonary nodule versus nodular scarring (from prior infection, inflammation, trauma, and/or other insult). Short-term follow-up with CT and/or PET/CT are both reasonable. If the nodule is hypermetabolic on PET/CT, biopsy is warranted to rule out cancer.
I have read that nodules are not uncommon and are often just a sign of past trauma. Have you followed up with your doctor yet?