Hello Tdue22,
Thank you for posting on Apple Support Communities. It sounds like there is an issue with your iPhone freezing, and it has persisted across several iOS updates.
If your iPhone has an issue where the display freezes, we might need to isolate it to either software or hardware. If the iPhone is already updated then make sure the storage is not full: How to check the storage on your iPhone, iPad, and iPod touch - Apple Support.
You mentioned that this issue is resolved when you close the app. If it's only a single app causing this issue, follow through these steps: If an app unexpectedly quits, stops responding, or won’t open.
Best of luck!