A phobia is an excessive or unreasonable fear of an object, place or situation.
Simple phobias are fears of specific things such as insects, infections, flying.
A social phobia is a marked fear of social or performance situations. Phobias are extremely common. The physical symptoms of anxiety may include a racing heart, shortness of breath, sweating, chest or abdominal discomfort, trembling, etc. and the emotional component involves an intense fear - of losing control, embarrassing oneself, or passing out. Commonly people try to escape, and then to avoid the feared situation wherever possible. With some phobias the person may have specific thoughts which attribute some threat to the feared situation.