Hi @Elpregunton, I am sorry to hear about this.
Your question has been translated to English as this is an International forum, please post any replies in English and it will be easier for me and other users to assist you.
Have you tried to connect different headphones to your phone in order to see if the behaviour of the headphone jack persists?
The first thing that I suggest that you do is to reboot your phone in safe mode to see if the behaviour persist there. All apps downloaded from Play Store is temporarily deactivated while in safe mode and by doing this you can see whether this is caused by a downloaded app or not. For more information on safe mode and how to use it, click here.
If the behavior persists in safe mode I suggest that you try to perform a software repair using a computer and Xperia Companion. Please note though that a software repair will erase all user data, so remember to do a backup of your user data first.
If none of these measures manages to improve the functionality of the headphone jack, I recommend that you get in contact with your local support team in order to have your phone sent to an authorized service center for examination and repair. If you have any questions regarding the service, such as routines, warranty and consumer laws, these type of questions are best answered by your local support team as well, as they vary between markets.
Try these measures and let me know how it goes!
