Well, this year I am having the same issue!! I too, used to be very flexible but now have pain in my hips even during sleep. I'ev thought for quite some time that my IT band was super tight, so have been stretching early in the AM, quick short stretches at work ( I stand all day) and again at night. It definitely has helped, although obvioulsy it's more useful AFTER I've either rode the trainer or been xc skiing. Of course, that's simply a given

I hope that your stretching helps and thanks for sharing!