After going through a lot of forums including this one it wasn't easy finding the answer to why i couldn't send or receive mms msgs on my S5. But this worked. Go to settings and then more networks. And go to network mode and check LTE/CDMA. Reboot and done! Try sending an mms to yourself and see.
I didn't have to remove or replace my sim card, just switching to lte/cdma and a reboot fixed it. But if just doing that doesn't fix it then the next steps would have been to remove/replace sim card.
I did have to remove the sim card but how easy that whole fix was. Thank you, now I will see how long it lasts. Everyone else get great signal with their GS5 out here except ME. Maybe it is just me and electronics but thank you!