Why cant i get any picture messages or group messages galaxy s4

[AC Question]

Ever since i got my galaxy S4 i cant receive any group or picture messages. It says downloading but when i scroll up then back down its like nothing is happening. My wifi is not on. My data is. Data roaming is on. I am using straight talk but i have never had troubles with this on any other phone. I had an s3 not more than 2 months ago and i didnt have any problems with it. I have tried 5 different apn's and only one will even give me 4g. i have looked everywhere online and i cannot find anything like this please help!!!