I've had back pain several times in my life and it's hugely distracting and limiting. I hope yours is better soon, or goes away completely.

An odd-sounding personal experience: I had chronic back pain for several years that went away a few weeks after buying a Honda (I'd been driving a Ford Taurus; this was in the 80s) -- the seat in the Honda was pushing on my lumbar region uncomfortably, but one day I noticed it felt fine. Turns out, the Taurus had too-little (none?) lumbar support and my spine was out of whack; the Honda fixed it, and my chronic back problem was gone. A firm lumbar-region pillow added to the Taurus might have done the same thing.

My wife and I have both been helped, for various issues, by an Osteopath. If you can find a good one in your area, he or she might be a good resource, and not just for back pain.

Several over-the-counter supplements can help reduce pain, although in my experience different people find help from different supplements (and some people don't seem to benefit from any, as far as pain relief goes. Depends on what's actually causing the pain, I suspect).

For example:

Several clinical trials have shown that PEA can reduce pain from a broad array of causes, including diabetic neuropathy, chemotherapy-induced peripheral neuropathy, sciatic nerve compression, carpal tunnel syndrome, osteoarthritis, low back pain, failed back surgery, stroke-related nerve pain, multiple sclerosis, dental pain, chronic pelvic pain, post-herpetic neuralgia, and vaginal pain (Hesselink 2012). In an observational study of individuals with chronic pain due to a variety of conditions who were unable to control their pain with usual therapies, adding 600 mg PEA twice daily for three weeks followed by once daily for another four weeks decreased average pain intensity scores in all participants who completed the study (Gatti 2012).

That's from https://www.lifeextension.com/protocols/health-concerns/chronic-pain# which includes a good number of other supplements that have been shown to reduce pain.

Life Extension (I'm a customer, nothing more, btw) sells a product with both PEA and Honokiol: https://www.lifeextension.com/vitamins-supplements/item02202/comfortmax

Once again, a large number of other supplements (vitamins B, C, E, and D; Curcumin, Boswellia serrata, and many other natural substances) may be helpful to you.

I hope you get some relief and are able to enjoy your trip.