For me, my sore scalp never indicates growth.
It straight up just means dirt. Oil. Clogged follicles that want to breathe.
It almost always starts with itching or discomfort, like the dirty scalp kind, then if I ignore it or I'm busy for a week, soreness. Once that happens (and I don't know if this is all necessarily related, but it's definitely the chain of events I've noticed), if I still ignore it, I shed easily, particularly in the sore spots. I begin shedding once the itching starts even, and REALLY shed once it gets sore. (Yes, I sometimes ignore it. My schoolwork can get crazy, and my hair can take a bit at this point.)
Now, I DO think that what can partially increase the shedding might be the fact that when it itches, I scratch and dig.When I touch my hair, I can pull out a LOT of shed hairs, especially when my shedding has increased, since other than the occassional digging or a random week of styling, I am low mani, practically no mani beyond making sure my hair does not matt. This is kind of unrelated, by I often liken it to how the petals will just clean fall off a flower and leave the stem if it's been in dirty water for a few days to a week.
So, since I do all that scratching and touching once it gets itchy/sore, I am sure that often causes a growth spurt, and that it's because of my digging, essentially stimulating scalp massages, not the itching. And of course, the "spurt" seems to be at the site of the itching, which is where I scratched most.
But for me, itching = dirt. Dirt and clogged follicles = shedding. Digging and rubbing = more shedding and growth through stimulation.