For as long as I remember the trapezius muscle on my left shoulder "pops" up if shrug/round my shoulders etc. I can't replicate this with my right arm (which is my dominant arm), my right hand shoulder is flat whilst left-hand has a definately bulge where the trapezius is. Its very strange looking having this single muscle bulging out of place and pretty uncomfortable.
I've had this all my life but it is weird. Is there anyway to pop the muscle back into the right place? Is this one of those things like having larger left pecs/feet/breasts etc due to it being the heart side? I.e. is this common?