You can see in the example images below that it says there's 6 updates available, but only shows 2 pending.
To fix this without leaving the app, you simply tap 10 times on any one tab at the bottom: Featured, Top Charts, Explore, Search, or Updates. This trick will also work in the i Tunes Store and in i Books (unless you have disabled the Store options in i Books, of course).
Think of it as a fresh start, while taking the proper steps along the way to ensure you have saved all of your content on your computer. If your i Phone is set to back to this computer, click on Back Up Now.
Also, make sure that you have imported all of your photos and videos.
With Lagu in your pocket you can slide to queue your songs to be played next, find lyrics easily from many sources or write them yourself. Why Lagu is so similar to the native i Pod/Music app?