Thanks for your query.
If your son is still complaining of pain in the right lower abdomen and is vomiting
then he needs to be examined by a doctor immediately. You also mention that you cannot put your finger on the abdomen and he is pale, tired and thirsty. The doctor shall do a physical examination and order appropriate investigations to come to a conclusion as the symptoms are pointing towards acute appendicitis
I hope I have answered your query to your satisfaction.
Wishing your son a speedy recovery..