pin and needle sensation at any age needs to be evaluated by a neurologist
generally it is due to some nutritional deficiencies at this age and rarely because of some anatomic or neurological abnormality like some kind of nerve injury
or compression, exposure to radiation or toxins, peripheral neuropathies (but not common at this age) etc.
genarally overall malnutrition
and specifically vitamin B12 deficiency
is most common cause. to diagnose this vitamin B12 level is available at diagnostic centres and along with this peripheral blood smear would help.
some other tests like imagings may be required.
you should consult your pediatrician
to discuss these possibilities and he may prescribe drugs like vitamin B12 or others as nescassary.
hiope my answer guides you well
wish your son a rapid recovery
Dr. Amit Kumar