I just saw a post on tundednut's Instagram page where a little girl was crying her eyes out in pains while her hair was getting done. You can hear the agony and know that she wasn't just being a brat. He asked if it was that painful and a lot of girls replied that "kids can be dramatic and annoying."
I'll say this on behalf of those annoying kids;

All Scalps are not the same.

Some people have really tender and sensitive scalp and no matter how gentle you are with their hair, it would hurt. There pain threshold is not lower than normal since they probably "chest " when you flog them but touch their head and it a different story.

That video brought back so many bad memories for me and now I'm wondering if it was even worth it. Nobody understood. It was always " look at your sister, see how quiet she is. Just shut up!"

Kids should cry when they are sad or being punished for bad behaviour and not when they are trying to look cute. "Beauty is pain" shouldn't apply to 7 year olds. It's not yet that serious.
As an adult, my scalp still hurt until 2 years ago when I went natural and started doing my hair by myself. Now I look back and wonder how I was able stand it as a kid when even as an adult my scalp would hurt if people touched it.
What to do?
Spray her hair with water anytime you want to work on it and use a leave in conditioner. Hairdressers may not want to do wet hair in Nigeria but talk to them.

Please wet her hair
She's not being dramatic
She's actually in pains
you just don't understand

https://www.instagram.com/p/BmaFu1Hn7Kl/?utm_source=ig_share_sheet&igshid=movcm4z8czl9

You still see tears in my eyes whenever I'm making my hair. Went natural last year, all I do now is cornrows and wear wig.
One of my daughters took after me, she doesn't like making her hair at all but sometimes she's dramatic about it.

I don't know why mothers stress their young daughters life all in the name of hair,some even go as far as braiding it with heavy attachments,and every time u see the girl shaking her head just to see what she is writing in class,I as an adult don't even do any hair that would touch my skin or disturb me,my girls would be on low cut but if they insist that they wanna plait their hair,then its gonna be simple weaven except for Christmas and easter periods