I am a German osteopath. I calculated in a clinical trail of 40 patients after a whiplash associated disorder, that coccydynia has become a "symptom" in 57%. The patients were osteopathically treated and it become better in 60% of cases.
To make the story short - now I am searching systematically, reviewing medical papers which are relevant to coccydynia to confirm your suggestion.
See Coccydynia caused by car accidents