HI, thanks for using healthcare magic Shingles can cause abnormal sensations such as numbness but this is usually limited to the area where the rash had originally occurred. It would be best for him to be evaluated regarding his current symptoms of weakness, muscle pain and tremors , to make sure that there are no other causes. This assessment would involve a complete history of his symptoms, medications , concurrent illnesses. General physical examination and neurological examination would also be required. Investigations would include bloods such as complete blood count, ESR and c reactive protein (both of these look for inflammation in the body), calcium, liver and kidney function. These are baseline, others may be needed. Treatment would depend on the cause found. I hope this helps