I have had chronic back pain for decades, and even now am in Physical Therapy and seeing a specialist for back pain management. Have ridden pretty much everything at WDW- Universal is a different animal altogether- lots of rides there I wouldn't go on. I wear my back brace- and have been mostly lucky- but have also made a couple of very regrettable decisions that put the brakes on the rest of the day- and made the rest of the trip doable but uncomfortable. We are headed there again in November, but nowadays I stick with the tamer stuff, and many days just go to enjoy the park without doing many attractions at all. My advice is to err on the side of caution, as one bad decision could turn your vacation into a less than pleasant experience. It is no fun traipsing around the parks in pain, and for me is no longer worth the risks I took on early trips. With that said, no one here can actually know what the specifics are regarding your back pain and what movements might trigger it, so I would rely on the opinion of your pain management specialist, or whatever physician you see for your particular issue.