First of all, keep in mind that I am unable to diagnose you because I am unable to examine you, this forum is for educational purposes.
I am also unsure if your headaches are related to your orbitofrontal osteoma. These lesions can be painful, but most often the cosmetic problem is what drives patients to surgery. The lesions are benign lesions that contain disorganized fibrous tissue and bone. The headache that you describe is consitent with chronic daily headache (also called tension type headache) and may be directly or indirectly due to your osteoma. For your headaches, I would suggest starting elavil (amitrypiline) 25mg at night (each night). You should start to have some relief in 3-4 weeks. The dose of elavil can be titrated up as needed. In reguards to surgery, I would attempt to get your headaches under control medically first. If you have tried 3-4 good headache prophylaxis regimes (elavil, topamax, nadolol, verapamil,etc) for at least 4-6 weeks each then I would push for the surgery (with the knowledge that the surgery may or may not help the headaches). If you would like to have the surgery reguardless of the headaches, then I would recommend that seek a surgery consult at a major academic center such as UAB University of Alabama Birmingham in your case. It is important to understand the risks of the procedure and not to overstate the potential benefits of the surgery (other than the cosmetic ones), but if the medical therapy fails, then surgery may be your best option.
I hope this has been helpful.