The actor has struggled with chronic aches and has even undergone three operations in an attempt to improve his condition, which he believes may have been exacerbated by the dangerous stunts he's performed onscreen.
Now Soul is lending his star power to a $1.6 million (£1 million) medical appeal to fund research into preventing back problems.
He explains, "What I'm mostly concerned about is that although I've been a sufferer over all these years, and probably not a lot can be done for me, it certainly can for other people.
"That's one of the reasons for this charity - the most significant point of this is to understand the causes in order to prevent it and treat it.
"Basically (the money will be spent) on researching the underlying causes of back pain - all kinds of back pain, whether it's nerve-related or muscle-related, if it's genetic. We'll even be dealing with stem cell research as well."
Soul is unsure if he'll ever be relieved of his symptoms, but he's grateful the affliction hasn't hindered his Hollywood career.
He adds, "It (stunts) didn't help. I think a lot of the action stuff that I've done in films over the years probably hasn't helped the situation very much.
"Thankfully it's never kept me from working. I've worked through the pain. You have to learn to live with pain. There's a threshold and you can live within that threshold. I'm in pain now, every day of my life I'm in pain. But somehow I can get through it."