While there are many claims, most of the hype is more marketing than proven science. Here is a consumer reports style list of some things that that seem to help. Remember that any treatment that gives you only temporary relief without progress over several weeks is probably not effective. Consult your doctor if you have questions. High First 12 weeks and for lost range of motion in sub-acute and chronic cases.
Chiropractors see a lot of whiplash cases and are therefore usually a safe bet.
Injured facet joints and joints irritated by loss of motion elsewhere. A good way to get severe neck pain calmed down so that rehab can take place. A good way to avoid surgery. A good way to avoid surgery or localize a level for surgery. A good way to calm down an inflammed SI joint so that other types of rehab can ensue.