You're lying down, trying to sleep. Some part of your body is itchy, scratching will wake you up, not scratching will remain itchy. Do you scratch or wait for the itch to go away?
I have this issue often. I know if I scratch, it will wake me up and take longer to sleep because of my body movement. If I don't scratch, my mind only focuses on the itch. Sometimes I'll wait 5 minutes for the scratch to go away and then I just cave and start scratching any minor itch I have on my body. Has anyone just not moved and let the itch subside or does everyone scratch?
I have this often when I go to bed directly after showering. I get itchy all over, but scratching makes it worse. I know the itch will pass eventually, so I just wait it out. I hate it though, so I try not to shower before bed.
Try checking if your shampoo or bodywash has Sodium Laurel Sulphate. A lot of people including me are allergic to it, and it can cause itchiness. There's a lot of options out there free of SLS, so try using products without it.