My iphone4 is the American version. I don't know why I haven't received any text messages these days. Who can help me?

There are several methods, but not all of them are effective. You must try to solve them. You can try setting, general and reset settings, or take out the SIM card, turn it off and on again, and then insert it. Or take out your SIM card, put another SIM card in it, turn it on, and test whether you can receive the message. (I recommend this method, because I didn't receive the text message before, so I can solve it by changing my SIM card. If you are using a mobile card now, you'd better try to change it to a Unicom card. )