Not getting texts after shutting off airplane mode

[the_game_rock]

I got a at&t Galaxy S4 Im using on straight talk. I got the apn settings to use 4G. The phone works awesome but I have noticed any sms or mms messages that get sent to me while on airplane mode I wont receive till about 6 or 7 hours later. Is there any way to get them instantly? I tried restarting the phone and I tried using the factory apn settings that came on the phone.

I had a razr I was using on Page Plus that used Verizon towers and it didn't have this problem I would receive my messages soon as I shut off airplane mode.
Thanks

 

[Rukbat]

It depends on the towers you're on and Straight Talk's arrangement with that carrier (and how Straight Talk has SMS set to retry). There's no "sync now" for SMS.