Burning Mouth Syndrome 
Burning mouth syndrome (also called stomatopyrosis, stomatodynia, and oral dysesthesia) occurs most commonly among women after menopause. The most commonly affected part of the mouth is the tongue (glossodynia). Burning mouth syndrome is not the same as the temporary discomfort that many people experience after eating irritating or acidic foods. Burning mouth syndrome is poorly understood. It probably represents a number of different conditions with different causes but a common symptom. 

A common cause is use of antibiotics, which alters the balance of bacteria in the mouth, leading to an overgrowth of the fungus Candida (a condition called thrush). Ill-fitting dentures and allergies to dental materials may be causes as well. Overuse of mouth rinses and sprays may lead to burning tongue syndrome, as can anything that leads to a dry mouth. Sensitivities to certain foods and food additives, particularly to sorbic acid and benzoic acid (which are food preservatives), propylene glycol (found as a moisturizing agent in foods, drugs, and cosmetics), chicle (found in some chewing gums), and cinnamon, may play some role. Deficiencies of vitamins, including B12, folic acid, and B-complex, can cause burning mouth syndrome. Iron deficiency has also been implicated. 

A painful burning sensation may affect the entire mouth (particularly the tongue, lips, and roof of the mouth [palate]) or just the tongue. The sensation may be continuous or intermittent and may gradually increase throughout the day. Symptoms that commonly accompany the burning sensation include a dry mouth, thirst, and altered taste. Other possible symptoms include changes in eating habits, irritability, depression, and avoidance of other people. 

The condition is easy for doctors to diagnose but difficult to treat. Frequent drinks of water or use of chewing gum may help keep the mouth moist. Antidepressants, such as nortriptylineSome Trade Names AVENTYL or anti-anxiety drugs, such as clonazepamSome Trade Names KLONOPIN are sometimes helpful, although these drugs may make the symptoms worse by causing dry mouth. Sometimes symptoms disappear without treatment, although they may return later.

More:
A small percentage of older men and women (mostly women), generally at, or around the age of menopause develop a problem with chronic burning pain and phantom tastes in their mouths.  It often centers on the tongue. The tongue itself looks perfectly normal.  It just develops a burning sensation that progresses throughout the day.  These patients may have seen numerous doctors to try to rid themselves of the annoying, and sometimes painful symptoms, but generally to no avail.  The problem has been ignored for centuries because there seemed to be no physical reason for the symptoms, and because it was believed that it was a hysterical symptom brought on by emotional distress.  In fact, the problem sometimes does respond to antidepressant drugs like Elavil.