The phone is very new, but I wouldn't be able to return it.
I did contact Sony, and their solution, so far has worked. They suggested to download, the PC-mobile companion app. And use it to fix the phone. Following the below instructions.
1. No matter what the program says do not connect the phone until you complete step 9
2. In the welcome screen you will see the different modules available for you including the "Support Zone" option. Click on "Start" below it.
3. On the next page Click on "Start" under "Phone Software Update"
At this point if you get an error stating that "Unable to install update components" or "Server is busy" , then please proceed to step 12
4. The program will say that there is no phone connected. Click on the option below that reads: "Repair my phone" the program will issue you a warning about the content that you will lose during the update
5. Choose the option to continue.
6. The program will issue a final message warning you of possible data lost during the update. Click on the checkmark and then on "Next".
7. After that, the program will download the necessary information (5 to 6 minutes) and it will present you with a list of phones.
8. Choose your phones model from the list then click on "Next" then you will see a new section telling you how to connect the phone. (don't connect it yet)
At this point the phone must be off and disconnected from the PC.
9. Connect the cable to the PC not to the phone, then while pressing and holding the indicated button (in the steps on screen an specific button will be shown for you to press on the phone) connect the cable to the phone and keep holding the indicated button until the program says "the update of your phone has started..." (in some cases a message of "Installing drivers" will appear before the message of "the update of your phone has started..." is shown.)
10. If you failed to follow the steps correctly the phone will turn on and it will request that you "Proceed with the following steps, slide down the notification bar", If this happens disconnect the phone from the cable, turn it off and repeat from step 9).
11. If the phone is connected properly, PC Companion will proceed with the update ( It will tell you to let go of the back key) then wait for the update to finish and follow instructions on screen to disconnect the unit.
Since doing that, I haven't experienced any issues. HOWEVER, as I've mentioned in my posts above, rebooting the phone to it's original factory settings temporarily fixed the stuttering, and using the mobile companion app as I have above, rebooted the phone as well, so it might be a temp fix. Also, I didn't install all the apps I normally installed, ONLY Facebook and Youtube. So it might also be an app that was causing the issue. I'm suspecting it MIGHT be 3G WatchDog.
I will update this thread if I experience the issue again, but so far, Sony's solution has fixed it.
Thanks for everyone's suggestions thus far.