More often than not, the Google Play Store download pending error means that other apps are updating at the same time. You may encounter this problem if you download multiple apps simultaneously.
Why is my play store download stuck on pending?
Check the internet connection
Check the internet speed if you are using Wi-Fi. Restart the router and device and try reconnecting. When using mobile data, ensure that the download via any network on Google Play Store is enabled on your device. Go to Google Play Store settings and check 'App download preferences.
Why is my play store pending?
Clear the Google Play Cache
This problem is prevalent when you have many apps that the Play Store needs to check for updates or perform other related actions. To clear the Play Store's cache, do the following: Slide down your screen from the top. You may need to do it twice.