I spend too much time at my pc or driving so get lower back pain. I recently found this workout that’s really good. It’s challenging but really works well! I sometimes have to ease back a little, especially on the last part, but it still helps.
Apologies, I can’t remember how/where to get alternative YT links.
Vegetable stir-fry, curry or similar should be easily do-able. There’s plenty of fresh veg that will keep long enough out of a fridge or canned asian veg is decent. Tomato or pesto pasta. Stew made with canned beef isn’t bad. Omlette.
Do you have a cool bag/box? Grab a bag of ice and you have a fridge for a few days. Even a plastic box would do the trick.