Neuralgia

Severe pain, usually sharp and paroxysmal, along the course of a nerve without there being any physical change in that nerve. 

Persons most commonly affected: Intercostal neuralgia: adults of both sexes, but more common in women over 50 years, especially persons who are already in poor health. Trigeminal neuralgia: adults of both sexes.
Organ or part of body involved: Any nerve or its branches, usually the trigeminal (facial) nerve, nerves that arise from the spinal cord and run between the ribs (intercostal) and the sciatic nerve
Symptoms and indications: Intercostal neuralgia: pain, usually on the left side, especially where the nerve leaves the spine in the back and in the front where it branches into the skin. The pain may come in intense bursts and may occur more often at a particular time of the day or night. There may be other symptoms, such as tingling, numbness or paralysis, and loss of appetite, and muscle wastage. Trigeminal neuralgia: usually on one side of the face; severe pain of a burning or cutting nature, which may be constant or spasmodic and may be provoked by simple actions such as eating or by heat or cold. The skin on the face may become inflamed and the eye on the affected side red and watery. The condition is very debilitating in that the pain can be so intense as to interfere with sleeping and eating. Hence, the person may suffer from loss of appetite and weight.
Causes and risk factors: Sometimes the cause may be inflammation or pressure on the nerve but often the cause cannot be discovered. Neuralgic attacks tend to recur from time to time in an affected person, especially if the overall state of health is low.
Prevention: There is virtually no way to prevent neuralgia, except to treat underlying diseases that may precipitate nerve damage and to avoid overexposure to chemicals and drugs.