Hi Robert,
Everyone says that kids go through certain things at certain ages. At two, children are learning that they are able to have control over their world. A four year old has learned this and attempts to manipulate this world.
Crying is usually indicative of frustration, and lack of control. Try talking to him and ask him if there is something that has been scaring him, or something he wants to talk about that's making him sad.
When he starts crying, have him stop what he's doing and sit down for a moment. Ask him why he's crying, and explain to him why whatever he is doing (not finding something, or not being able to do something), is not worth crying about, and in fact, could make doing or finding it even harder. Let him know that if he cannot stop the behavior, then he will have to do a "time out" each time he starts.
You can in fact make a "cry station" where he has to go sit, if he feels he has to cry. When he is done crying, then he can come out of the time out. This works very well, because it makes them think about the behavior when they do it.
I hope this helps, if you have any further questions, feel free to ask, it costs nothing to click reply. If this has helped, please remember to click the green accept button.
Warmly,
Chase
#1 Just Answer Parenting Expert
Just Answer Parenting Mentor, Emotional, Behavioral & Physical Issues. Babies to Teens.