I am suffering from SI joint pain so severe that I can't stand erect at times. I am confused, however, because I saw a pain management doctor who told me my problem was degenerated discs in my lumbar spine. He then gave me a steroid shot in my spine and, lo and behold, the pain in my SI joint disappeared for about a month. How is it that degenerated discs can manifest solely as SI joint pain? Do I treat myself for DDD or SI joint dysfunction??