For The Last Few Months I Seem To Have An

for the last few months i seem to have an uncontrolable itch and will start in one area of my body and seem to lead to other parts of my body. I start to scratch uncontrolablly and i end up with hives. i can't seem to satisfy the itch with scratching and i end up scratching so hard and long that i end up with welts and cuts. it started a day her and a day there and now it seems to be more frequent and it'll keep me up at nite and has been even more of a bother when my insomnia acts up. I should also mention that i have been diagnosed with psoriasis but it's only confined to my scalp. is there any tests that i should be doing? any blood work i should be doing? when i look up symptoms it talks about fibromyalga and MS. i just need some help so i can get some answers.