My son is almost 4 years old and he still throws tantrums, crying and screaming hysterically when he doesnt get what he wants or is made to wait for something. Is this normal at his age? How do i make him learn to wait?

Make a game out of it -- ask your child to count to a certain number (depending on how far he can count) while you complete the task at hand. This will distract him and help him improve his counting skills. My friend uses this method to teach her daughter to be patient when she is hungry. Sometimes, she will ask her little girl to sing along with her as she goes about preparing her milk or juice.