It is a real short term relief right when you first get off after hanging upside down back and forth for 15 minutes. Here again you are working against the tight back muscles in your back and they won't let go even hanging upside down.
If you could overcome the tight muscles it would give you great relief. Those muscles are holding strong, it takes time with a change of a different routine of lifestyle to get those back muscles to stretch out again. Kind of like that "Growing Pains" thing growing up as a kid, when your legs would grow faster (longer) than your leg muscles could grow, causing all kinds of leg pain when trying to sleep at night. Going through that growing spurt as a youngster.