Sciatica, slipped disc or kidney stone - how to tell the difference?

I had a confirmed kidney stone over 10 years ago. It was one of the most painful experiences I’ve ever had to deal with. Since then, I’ve suspected that I’ve had four more kidney stones, all air travel related. This excruciating pain tends to show up about 48-72 hours after I’ve been in flight, with my most recent occurrence happening last night. I haven’t experienced blood in my urine, nor have I spiked a fever or felt like vomiting like I did the first time. I was prescribed pain medication for kidney stones which help manage the pain to some degree. I’m wondering, however, if I’m actually experiencing sciatica nerve pain or a slipped disc. How can one tell the difference? The pain intensifies if I stay idle for too long or when I lie down. Again, it’s happened the last four times I have traveled, 2 domestic flights, and 2 international flights. My doctor thought it was probably due to becoming dehydrated, so I made sure to drink a lot more than I typically would this last trip, but I am once again super painful at base of my back (about at the waist) that travels down both buttocks.