I'm sorry this is happening to you. I've been having some issues this week with really bad spasms in my back and I still think back pain is the worst. I hope you find something that can give you relief. I haven't been taking any pills for it (I see the doctor on the 10th so I am trying to wait until then to talk to the doctor about it) but the best things for me have been to take hot baths with epsom salts and to sit with an electric heating pad behind my back. They don't make the pain go away but they do take the edge off a little so at least I can breathe most of the time without it being so bad that I want to throw up.

But as far as your trip...try to enjoy yourself as much as possible. We all have our limits but just try to enjoy the things you CAN do and not get yourself down about the things you can't. Good luck...I really hope you have a great trip and that your doctors can find something that helps you.