Stretch in the middle back when doing HS stomach to wall

When I do stomach to wall HS and I try to open up my shoulders to the maximum I feel a good stretch in the middle of the back(higher than the lower back just there in the middle) maybe this area holds my handstands down and not my shoulder mobility .What do you think?

I can't tell you exactly WHY this is happening, but i can tell you that if it is hindering you abiklity to progress, definitely try and stretch that area out before an after you work on your handstands. I have never felt a pull in my back so i really can't tell you why its hppening. But any weird things like that, that have happened to me after a few days of stretching it out its back to normal

maybe its the end of my lats or I dont know just I feel horizontal stretch in the middle of the back

your back is probably a bit tight but unless it's uncomfortable I doubt it's holding your HS back.

Simply hang on a bar and rock back and forth besides doing seal and pike stretch in your WU.