Hello there Nathanmilosh,
Thanks for posting here on the Apple Support Communities! This is a place where other Apple users can submit questions or respond to others to help lend a hand. Let's take a closer look as we do our best to provide some additional insight.
We understand a specific stock seems to be stuck in the Stocks widget. To get started, have you already tried completely removing and adding back this specific widget like new again? Use widgets on your iPhone and iPod touch
If that doesn't work, then we may suggest both removing the widget and uninstalling the Stocks app before reinstalling it again: Remove built-in Apple apps from the Home screen on your iOS 10 device or Apple Watch
Any change after the reinstall?
We hope this helps get you pointed in the right direction.
Take care.