2nd trimester And I'm itchy as hell

Totally did not experience this with my son but about 2 weeks ago, I'm 18 weeks now I started getting REALLY ITCHY on my scalp, neck, and upper back and I havr no clue as to why I haven't used anything new not detergent nor shampoo, body wash and it's driving me absolutely crazy! Especially behind my ear😠 And my shoulders. I have a doctor's appointment Wednesday so I do plan on bringing this up I have been checked for lice by my mother and I'm clear so anyone else ever feel this way? ???