Mummies does ur bb does these bahaviors?

Hello mummies, I’ve noticed that my baby, who is now 6 months old, displays the following behaviors: Frequently arches his back and tilts his head back, while I’m carrying him or feeding him in the baby chair. Rubs his head from side to side against surfaces like the stroller or bouncer. Like to hit his face against the playmat during tummy time. Could you share if your babies also display these behaviors? Does ur bb eventually stop doing this at what mth? I’m worried and wondering if these are normal. Thank u mummies