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.
Behind the scenes.  1 Johnny B. Goode was actually composed and first performed by Chuck Berry in March 1958. 2  Michael J. Fox's performance of the song is one of the signature moments of Back to the Future. 3  During the part where Marvin is calling Chuck Berry, Marty starts doing Chuck's famous duckwalk.