When you met the process of spontaneous symmetry breaking (SSB) for first time (in my case during the standard model course) they tell you the example of a (3D) ferromagnetic substance. In the case where $T>T_{c}$ (critical temperature) the magnetisation: $$\langle\vec M\rangle = 0.$$ Instead, if $T<T_{c}$ we have $$\langle\vec M\rangle \neq 0.$$ In this case $SU(3) \to SU(2)$ and you can observe either the magnetisation “state” after and before the symmetry breaking experimentally (varying the temperature) so we can say it’s physical, in the sense it is a “dynamical” process.
My doubt is: is it the same if we’re taking about SSB in electroweak theory ? Can we reach temperature (or energies) where the $SU(2)_L$ is still a symmetry of vacuum state and observe it? And what’s the physical meaning related to have a $m^2$ term that is negative, is it related in some way to the running of the coupling and renormalization? (I mean do I have to interpret all the masses as functions of energy scale of the process?)