Excessive tactile stimming causing pain

Hi all. Sorry for the long post. I got a diagnosis of Global Developmental Delay at 32 so not autistic per se but I desperately need help with a tactile stim that's causing bad muscle skeletal pain from repetitive movement.

I like to feel my hair strands individually. When I feel my hair I'm looking for a strand that's more course and bumpier than the rest of my hair. It's SO stimulating to touch them, but then I pull them out because it's 'wrong' to have a different texture other than smooth on my head. Then I start doing it again to find another bumpy strand, rinse and repeat. All day long. I started doing this when a classmate made fun of my frizzy hair when I was 15 so I had to feel my hair to get rid of the bumpy strands, until it started feeling so good and I haven't been able to stop. It takes up so much of my time and now I got recurrent shoulder pain from it.

I have a therapist and I don't think she believes it's as bad as I make it out to be because I don't do it in front of her. She told me to practice mindfulness, do yoga and listen to binaural beats. It's not working. What on earth can I do to decrease the frequency of this behavior?