Hello. Thank you for coming to JustAnswer with your question, and welcome.
Do you take any medications (prescription or OTC)?
Your symptoms seem to match a B12 deficiency. Your back pain could be related but is probably coincidental. Since chiropractic is helping, this was most likely an injury or overuse issue with your back muscles.
B12 deficiencies are more common than most people realize. To absorb and utilize B12 from food you need stomach acid and "intrinsic factor". As we age, the stomach acid production can decline, or your stomach can have some inflammation that impairs the intrinsic factor production. This can be remedied by taking B12 supplements, even by mouth. In studies, B12 supplements in oral form has been shown to be better absorbed than B12 from food.
Taking antacids, acid reducing medications and laxatives can also impair absorption of B12.
Any other problems that would cause numbness and tingling all over would be neurological in origin. So if the B12 doesn't help you, you should get a referral to a neurologist. Your symptoms could also be due to nerves being impinged in your spine, but you would probably have to have multiple areas of problems for all areas that affected, starting in the cervical spine. An MRI might show some problems, if your doctor feels it is warranted.
Here is some good information about B12 levels and supplements.