you say is probably an inguinal lymph
gland being inflammed. / Does he have fever
too ? see for any problem in his legs, toes, thighs, anal or scrotal area. If so he may need immediate attention . you have to consult a doctor soon.
But if there is no other problem you can wait for your for your paediatritian to come.PLease tell the dr. about all of his complaits.& get releived of the tension.
Some times when lonely children complain of such varied complaints ,to attract parents attention. If this is neglected it may affect intellectual & emotional devolopment of the child. working & bussy parent should therefore give a quality time to their children, be always +ve to them,Careful about physical/emotional/intellectual devolopment of their kids.