There are several things that could be causing your issues with receiving texts. It could be a malicious app that you may have downloaded or simply having way too many left over text logs that are using up all of your phone's resources. To start, I would first suggest to go through and delete every third party application that you don't use much and isn't completely essential to your everyday use (you can download them again later, I just think this would be a good first step to finding the issue). Once you do that, I would suggest clearing the data of the Messaging application. (WARNING THIS WILL DELETE ALL OF YOUR TEXT MESSAGES SO BACKUP ANY IF DESIRED). To do this navigate to the settings application>then find the "apps" section>(scroll over/navigate to the "all" apps section)>locate the messaging application>then press "Clear data". It may take a second to delete all of the text messages, just be patient. I feel like this is the first step I would take in order to try to solve your issue. If this step works, I would suggest also changing the text message limit to as low as you prefer (I leave mine at 200 which is more than enough for me) in addition to lowering the Multimedia message limit (I set mine at 10) so you won't encounter this issue in the future. Lowering the text/mms message limits is done within the messaging application settings. Simply open the messaging application, press menu>settings (within the messaging app) and you will see the options I am referring to. Deleting old, unused text logs in the future can also be a good habit in the future just so you don't have so many unused, old text logs taking up resources.
If none of this works, I would suggest a factory reset, which takes your phone back to how it was when it came out of the box (all user data deleted) and is a slight annoyance for the everyday user who isn't used to wiping their phone on ocassion. I hope this helps you out a little bit. Good luck!
