Hello Paddy4321,
Welcome to the Apple Support Communities. I understand that you're seeing an "Error in application" message appearing on your iPhone frequently.
Good thinking in uninstalling apps which you had installed over the last month. With the error still occurring I would work through these steps:
1 - Quit all apps which have been opened on your iPhone with these steps: How to force an app to close on your iPhone, iPad, or iPod touch.
2 - Restart your iPhone.
3 - Try not to use your iPhone (unless necessary) over the next hour to see if the error reoccurs. If the error reoccurs without any use of your iPhone, Contact Apple Support for more assistance.
4 - If the error has not reoccurred, being using your iPhone one app at a time. As soon as the error appears, make a note of which app you opened last. You'll then want to uninstall that app. Continue using your iPhone and see if the error returns.
5 - If the error does not return after removing the app, you can then try reinstalling the app. If the error returns after you have reinstalled the app, you'll want to contact that app developer for more assistance: How to contact an app developer.
All the best.