Thank you so much for this.

I'd never heard of stimming before, but your first paragraph was exactly what I feel that I have. I just couldn't write it as clearly.

It seems to be caused by all sorts, as you suggest:- stress, focus, boredom. Because of that it just makes it seem like a habit that I'm always practicing as somewhat opposing moods (focus and boredom) trigger it.

I've never been diagnosed, but I've always shown signs of autism in general and I believe other people view me that way even if unspoken. Regardless, I read a bit more after reading what you've written, and found it's common to a lesser degree even without autism, so whether I am autistic or not, it doesn't matter.

I'll try to replace the stim with something else less destructive, like squeezing my wrist/bicep as that's something to do "on the way" to my hands reaching my hair. I think when I started biting/chewing my inner lip, this was something like that (ie. getting the same feeling as the hair pulling stim without as much time to move my hands about).

Thank you again. I had no idea about this and it's given me a great starting point to find out more and try to work around it.