I have not been able to find an answer as to what is causing my 5 year olds itchy pain on the bottom of his feet. The bumps are under the skin and do not break the skin, also they are no where else on his body.
Have you taken your son to the doctor for this? It could be something as simple as a fungal type infection.
Here is a post with information about athlete's foot.
It could be an allergic reaction, eczema, chigger bites...the list goes on. You won't know what this is or how to treat it until he is seen by a doctor.
I hope you find the cause soon. Thank you for your question.