What can cause a small bump on my shin that aches at night?

Orthopaedics consult: If you have significant night pain, an osteoid osteoma comes to mind. However, the best answer is to refer you to an orthopaedic surgeon for a full history and exam. Imaging such as x-rays helps in the diagnosis of such issues. Have you had any trauma to your shin? Playing sports? Your physician will be able to look at your leg in person and give expert advice. Good luck.