Hi, I am sorry to hear of your MMS coming individually, and can see how that might be annoying. First, have you tried Safe Mode? It can help indicate if a third-party application may be to blame: https://www.samsung.com/us/support/answer/ANS00062983/
Also wiping the cache partition can help clear up some misbehavior. The steps are:
Performing a wipe cache partition removes any temporary files that may be causing an issue with the device. All personal files and settings are not affected by this option.
- Ensure the device is powered off.
If the device is unresponsive/frozen, press and hold the Power button (located on the upper-left edge) for approximately 10 seconds or until the device power cycles.
- Press and hold the Volume Up button (located on the upper-left edge) and the Home button (located at the bottom in the middle).
- While continuing to hold the Home and Volume Up buttons, press and hold the Power button (located on the right edge) until "RECOVERY BOOTING" appears in the upper left then release all buttons.
- Select wipe cache partition.
Utilize the Volume Up/Down buttons to highlight and the Power button to select.
- Select reboot system now.
Option is highlighted, utilize the Power button to select.
Lastly, you can try a factory data reset. Before doing this, make sure to back up any data you do not wish to lose, as a factory data reset WILL erase all data still on the phone. https://www.samsung.com/us/support/answer/ANS00062029/
Please let me know if this helps.