I Have A Phantom Itch On My Back Under My

I have a phantom itch on my back under my left shoulder blade that itches so bad that it wakes me up at night , it happens every year, it goes away for a while and then come back , well its been coming on steady for the past 4 days and last nite it woke me 3 times, I had to sit up and get the back scratcher to get relief,