My 4 years old son is crying a lot not at all stopping even though I and mu husband tries to convince him .He hits his head with his hands whenever we don't buy any toys or food for him. In public also he throws a lot of tantrums until and unless we don't fulfill his demands.He hits himself and scratches his body with his nails.Nowadays it's becoming too much. I and my husband really not able to understand what is actually going on and how to handle him.Please suggest.