If i have tingling
 

... in the area behing strecthed, sould i stop or is it a good sign ?

I guess it depends on how much tingling..
like it is from stopping of blood flow because of the arm position?

or is it an internal tingle like scar tissue/fascia loosening up?

second, a little tingling on internal scalenes triangle and a strange sensation of something going off you know
And one time a song from my neck