Am i gonna die,my head jerked forward on violent braking(40kmph) and my neurologist says its just muscle strain,no xray nothing.

Likely No: You likely suffered whiplash which is muscle strain. Unless you have other symptoms of further injury (which I am assuming you do not considering you have already been examined by a neurologist), then you need rest, NSAIDS or natural forms of anti-inflammatories, neck support, and PT exercises. You do not want to exacerbate an existing muscle strain.