Can applying volterol, biofreeze etc, to your whole back help backache?

Yes but temporarily. Volterol is an anti-inflammatory. It may help but will only be temporary. It should not be a long term strategy without physician supervision. Biofreeze is about the same as using ice, again temporary relief at best. Since most back aches are temporary this is a reasonable strategy. If it doesn't help after a few tries, see your doctor.