Music purchased via my iphone 4 from itunes prior to upgrading to ios 5 will not play on my iphone after the upgrade. When looking at the "purchased" playlist on the iphone it appears empty and songs purchased via my iphone are missing from other playlists. When I view the same playlists on the iphone via the itunes interface, I can see all of the songs that appear to be missing (but are acutally there); however, when I try to play them from the itunes interface, I get an exclamation mark next to the song name. When I right click to Get Info, there is no album cover and all information displayed is grayed out. The songs (which were transferred to itunes) play fine from itunes. I am not having any problems with songs purchased from itunes via my computer or songs not obtained from itunes; just songs purchased using my iphone. I only have one itunes account and it hasn't changed. I am not using iCloud. I have tried restarting my iphone and resynch-ing those songs. Neither have helped. Feel like I'm missing something basic. Anyone have any thoughts?