i dont think its possible to have tos (scalene kind not just pec minor or bc of cervical rib) without forward head posture.

fhd=increased likelyhood of tmj

also my experience is i never experienced a neck spasm in my life until i irritated my bp (despite giving myself whiplash and having no cervical curve) which i find interesting. so it goes both ways, muscle to nerve irritation nerve to muscle irritation