Media player doesn't show songs
Note this part in your description:


  ...The songs will not show up unless I restart the application several times...


Every reboot or finished USB connection will broadcast a android.intent.action.MEDIA_MOUNTED intent to apps. Media Storage captures this...



...and triggers a re-scan of the media library. If you have a very large one, the Media Storage is probably re-scanning during that period (could take minutes, depending on your phone's specs), thus the library is temporarily unavailable.