I'm terrified and worried

Hi mommys.

Yesterday we went to the pediatrician because my baby, who is 10 weeks old, arches far behind.

However, as the doctor had a hard time getting her to sit down, she had her head scanned because she said she found her too rigid.

Now I'm terrified because I've been searching the internet.

She is only two months old but she's starting to open her hands, and this morning I was able to sit her down at first (because she was sleepy and had just eaten) so she was soft.

Can anyone tell me about this?

Does anyone have slightly stiffer babies who are healthy?

Thanks 🙏🏼❤