Tossing and turning causes breakage due to friction from standard cotton...
https://nova-wiki.win/index.php/How_Do_I_Keep_Long_Hair_From_Getting_Rough_and_Dry_Overnight%3F
Tossing and turning causes breakage due to friction from standard cotton pillowcases. Switching to silk helps, but you can also try a loose braid or a silk bonnet to keep your ends protected while you sleep