My body itch after having a shower. i have changed body soap uncountable times. is there a medical condition responsible for this?

Itching: if you are take hot showers you may have cholenergic urticaria, a form of hives caused by heat. Another condition is called aquagenic pruritis which is usually seen in people allergic to water. In both cases a dermstologist should be consulted

Dry skin: Using very hot water and harsh soaps can be drying for the skin. Try decreasing the temperature of your bath/shower water. Blot your skin after bathing and then apply a moisturizer. If this does not help see your physician.