William O. Roberts, MD, a family physician at MinnHealth, in Minnesota, and vice president at the American College of Sports Medicine, likens a stress fracture to bending a paperclip back and forth: Eventually you get little cracks. While stress fractures are pretty common in the lower extremities -- the shin, foot, ankle-- they can also occur in the back or in the arms, says Nicholas A. DiNubile, MD, an orthopaedic consultant to the Philadelphia '76ers and the Pennsylvania Ballet.
A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. Headaches can result from a wide range of causes both benign and more serious. Brain tissue itself is not sensitive to pain as it lacks pain receptors.
A migraine is a type of headache. It may occur with symptoms such as nausea, vomiting, or sensitivity to light and sound. In many people, a throbbing pain is felt only on one side of the head. A migraine headache is caused by abnormal brain activity. This activity can be triggered by many things. But the exact chain of events remains unclear. Most medical experts believe the attack begins in the brain and involves nerve pathways and chemicals.