From the history,One of the possibilities is sinusitis
which may follow an acute cold. I suggest you to have your child examined by an ENT specialist
who may order an x-ray of para nasal sinuses
and treat the child by steam inhalations, nasal decongestants and appropriate antibiotics.
The other possibility , I can think of is Migraine
which may follow an upper respiratory viral infection in about 30 % of patients. You may be asked to get a CT Scan
of your child' s brain done as a baseline work up to exclude any other cause of headche if it persists beyond two weeks. So you should consult a paediatrician who may evaluate the child's problem and manage accordingly.Also get his eye and vision tested by an ophthalmologist.