The classic pattern is delayed. Something jolts the head suddenly, you feel shaken but fine, and the next morning the neck has seized. That delay is normal — the tissue reaction takes hours to build.
What is actually injured
The muscles and ligaments of the neck get stretched beyond their normal range in a fraction of a second, without time to brace. The result is a strain, plus a good deal of protective muscle spasm.
Anything involving significant force needs checking medically first. After a car accident, a fall from height, or a heavy collision, get assessed for anything more serious before booking soft tissue treatment. Massage is for what is left once bone and nerve injury has been ruled out.
What treatment involves
Early on, gentle work only — settling spasm, restoring some movement, and keeping the area from stiffening while it heals. Aggressive treatment on an acutely strained neck makes things worse.
As it settles, more direct soft tissue work, joint mobilisation to restore rotation, and exercises to rebuild the control the neck lost while guarding.
How long
Most simple neck strains settle over a few weeks. The stiffness tends to outlast the pain, and the people who get stuck are usually the ones who kept the neck completely still while it healed.