It's cross to bear, bear in this case being used in the same sense it is in weight bearing, Greeks bearing gifts or even ball bearing. It refers back to the Biblical tale of Jesus carrying his cross to Golgotha.
Lookin' Out My Back Door. Lookin' Out My Back Door is a song recorded by the American band Creedence Clearwater Revival, also known as CCR. The song was written by the band's lead singer, guitarist, and songwriter, John Fogerty.
Knocking at Your Back Door. Knocking at Your Back Door is a song by the British hard rock band Deep Purple, the first track of the album Perfect Strangers, which was released in September 1984. Song was written by Ritchie Blackmore, Ian Gillan and Roger Glover. The track was widely broadcast by the media of that time.