What Is It When You Break Out In Hives But

what is it when you break out in hives but they come about in a different spot everyday? I thought it was the histamine in the green tea that i was drinking heavely but i stopped that 4 weeks ago when i first noticed the hives. I had a cortizone shot and cortizone cream and benadryl and the hives have not stopped. how do i stop the itching!