Thanks for the reply.
I have no SD card installed. Never have
Try a cache partition wipe, if you haven't already:
https://support.t-mobile.com/docs/DOC-30240
If that doesn't help, then it might be a corrupt media file on internal storage. This is more of a hassle, but you can try connecting your phone to your computer via USB and backing up all of your media to the hard drive (photos, music, videos). Then delete them all from the phone. Remember to include all media, including things like custom ringtones, as suggested by cohoman. The directories you should be looking at are /DCIM/Camera, /Ringtones, /Notifications, /Alarms, /media, /Movies, /Music, /Pictures, /Podcasts, and /Download.