Hello Twall275,
It sounds like you are having an issue where you hearing a beeping sound when you use the volume buttons. If this is occurring in the Sound & Haptic section in settings then this is normal to test the sound levels.
If this is happening any time you use the buttons, then I suggest to reinstall the software in your iPhone to help rule out any software related causes.
This should not affect any of your data, but it is always a good practice to make sure you have a current backup in either iTunes or iCloud. How to back up your iPhone, iPad, and iPod touch
Once you have a current backup, follow the steps in the section titled "If your device turns on but gets stuck during start up" from the following article. These steps will reinstall iOS. Keep in mind that these steps were written for a different issue, but they will still help isolate the situation further. If your iPhone, iPad, or iPod touch won't turn on or is frozen
After you reinstall the software, test out the buttons to see if you still hear the beeping noise.
Cheers!