Claustrophobia is morbid fear of enclosed spaces.
There is no one cure for it, but there are various treatments, any one of which may help you improve significantly or completely overcome your fear. Exposure therapy is a behavioral technique that seems to be the most effective, long-lasting treatment for specific phobias, including yours. The two most popular forms of this therapy are systematic desensitization and flooding. Systematic desensitization is a slow, gradual exposure process incorporating deep-muscle relaxation and visualization. Eventually, you work your way up to experiencing the situation you most fear, but by then, you are desensitized and in a relaxed state of mind.