Clearly, people that do this night after night on Broadway have been well trained HOW to do this correctly. Chances are, you are YELLING - constant pressure on your vocal cords - and therefore, it sounds terrible, and you are you hurting your vocal apparatus. Fine a good teacher - degreed, certified, experienced - who will help you. Meanwhile - quit playing with fire.
Taught vocal and Choral music full time in the schools of NY for decades.