There are times when I've had significant join pain, usually during the winter months and after some exercise...
This is a simple cream which can be made with minimal ingredients and only simple tools.
http://www.askaprepper.com/homemade-hot-pepper-cream-arthritis-joint-pain/It is quicker to apply than taking a hot bath (although that works too).
If you use a container with a good seal, you can pack this in your BOB without fear of leakage. You can also find "toothpaste" tube style containers at some "outdoor/camping" supply stores. These have a seal-able bottom seam that opens and will allow you to spoon in the cream.
Hope this helps someone else too.