Why do I hear a popping sound in my left clavicle when I perform a chin tuck?

[yirma19]

I have somewhat forward neck posture (probably due to mild lordosi), when I chin tuck and push my head backward I hear my left clavicle popping. Coincidentally its also my left clavicle which seems to be a bit more tilted than my right which is basically straight.

 

[Deleted member 26859]

means u aint built for that movement. do soemthing else