What causes hand pain, numbness in legs, face, arms and headache?

Numbness: With that constellation, consider a metabolic or electrolyte imbalance such as calcium, sodium, potassium, etc. It could also be independent problems of carpal tunnel syndrome, cervical radiculopathy, or headaches from other causes.

Many symptoms: There are many possible causes of these symptoms. Any one of these has a few causes. Considering the pain and numbness is in multiple places, a problem with the nervous system or the joints could be a factor. The diagnosis depends on any other symptoms you have, what your physical exam looks like, and test results. A diagnosis that unifies all your symptoms may not be easy to make.