What Causes Headaches And Itchy Scalp?

I have been having severe headaches and itching in my head since I left the beauty shop and got a perm bad headaches in the back of my head and scalp itcheing severly is it the chemicals or what it has been going on almost a month I have washed my hair 4times a weak I even ended up in the er they did a cat scan to make sure that I was not having a aneresym scalp still itching bad headace not as bad right know.