I thought some more about this. I'd like to know how many people with ED have back issues vs the general population. If the percentage is similar, then it's entirely possible his back issues are rooted in psychological stress.
A summary of the research on the subject as of June 2021 can be found here[1], but I would caution you about the way you're approaching this. It seems like you're letting your hypothesis drive what you want to observe, rather than letting observations drive your hypothesis. That is to say, it seems like you're looking for a connection between stress and back pain, rather than looking at the evidence and letting that tell you what's connected.
There's a pretty clear correlation between specific genes and EDS, and there's a pretty clear connection between EDS and chronic lower back pain ("cLBP" in the study). There's a connection between EDS and "psychological distress" noted, but the authors seem to indicate that EDS is causal in both the psychological distress and the cLBP, not the other way around. There's no noted correlation between psychological distress and cLBP. On the contrary, it seems like psychological distress and cLBP are actually correlated with different variants of EDS.
"Is back pain in an EDS patient caused by stress?" is a valid scientific question, but it's not one that's likely to yield any interesting results if you test it, because so far I see no evidence, even anecdotal, that the two might have a causal relationship. There are higher-priority questions to investigate that are more likely to yield interesting/productive results.
Love your analysis. And I appreciate you cautioning me on my approach. The interesting thing is I believe your attempt to find answers based on data here is the biggest trap there is when looking at back pain. Are structural issues with backs the cause of back pain? In Sarno's book he talks about how people will often feel back pain and then search for an answer. As a result they'll get a bunch of tests done and perhaps find that they have a bulging disk or some other abnormality. Then they assert that the bulging disk is the reason for their pain and perhaps consider some expensive invasive surgery. However, a huge proportion of the population has a bulging disk with no pain associated. Sure it's possible that the ones with pain are different from the ones without. Except back surgery rarely cures the pain and instead leaves people with life altering mobility issues permanently. Sadly it's often difficult for people to deal with psychological issues because they don't know where to begin. They might not even notice the things that bother them because they bury them so deep. In western culture it is much more acceptable to get metal rods shoved into your back than to see a therapist.
