Neck *fixed* after hit to head

[Smf123]

When I was in high school my neck began to feel "stuck" when I would try to tilt it all the way back. It felt generally stiff but when I would tilt it back I would quickly hit a point where it would be too tight and too painful to go any further. I visited a chiropractor regularly who performed neck adjustments, which made it feel a little better but at no point fixed the stuck feeling when tilting back.
Then one day I was messing around and boxing with a friend with gloves on and he hit me right in the face and my head snapped directly back and I heard a loud cracking sound and fell to the ground, body tingling. I stood up and my first words were, "I think you just fixed my neck." I immediately had full range of motion restored. To this day ~11 years later I still think of it as the day my neck was fixed and I've always wondered what happened internally. Thoughts?