MY SCALP GETS VERY,VERY ITCHY. I SCRATCH IT SO MUCH

MY SCALP GETS VERY,VERY ITCHY. I SCRATCH IT SO MUCH I GET SORES. I AM MISSING HAIR SPOTS ON THE SIDE OF MY SCALP FROM THE ITCHING . I HAVE TRIED DIFFERENT SHAMPOOS WITH NO LASTING LUCK. I HAVE USED MIDICATED SHAMPOOS AND DANDEROFF SHAMPOOS. I DON'T KNOW IF IT IS CONNECTED BUT I GET SORENESS ON THE SIDES OF MY SCALP AND HEADACHES IN THE SAME PLACES. SUGGESTIONS PLEASE. THANK YOU IN ADVANCE, BILL