Probably not any head injury or re injury... but that is a lot of repeated effort for neck/shoulder muscles..
Do they feel tight or sore at all?
Sometimes it is hard to tell if they are slightly affected already. by any sort of whiplash or if neck/shoulder were involved in the past injuries.
All those muscles can tense up and make for many symptoms..
*esp if you mainly do deskwork for job..* RSI can be a factor also..

I would try to do some general muscle strain home care on neck/shoulder muscles.. OTC for pain/inflammation, heat/ice, massage if you can do it or get someone to do that
maybe even some trigger points developed, you can google for how to check & do self care for those too..
here's some info-
Trigger point information {TrPs} for short