I guess your download manager stuck, I did see this in the past many times. Try this:
Go to Settings -> Apps -> Manage apps -> upper right corner 3 dost menu -> Show system service -> go to the search field -> search for Download -> you will see 2 apps: 1 is the Android download manager (com.android.providers.downloads) and the other one is the actual GUI for the download manager (com.android.providers.downloads.ui) -> clear the app data completely for both (don't worry, it won't delete any of your files) -> Go and search for the Google Play Store -> Force stop -> Clear cache -> restart your phone -> Go back to Play Store and download Waze or anything else that didn't work.