Hi welcome to Health care magic forum.
Thanks for calling H.C.M.
The cause of headache may be any thing, it is to be investigated and find out. If the numb ness on one side is associated with with head ache it must be concerned, I advise you to consult a neurologist
for diagnosis and treatment.
You may need to have a C.T.scan for confermation of the cause.
Other causes may be sinusitis
, mental tensions, etc may be considered.