How did he injure his neck?
At Summerslam 1997, Austin was wrestling Owen Hart for the Intercontinental title. During the match Hart did a tombstone piledriver on Austin with his neck bent in the wrong angle causing temporary paralysis to Austin. Austin finished the match and won the title but serious damage was done to his neck. Austin has never fully recovered from the injury, which is why he has changed wrestling styles from technical to brawler.