Yes, your neck .. always a royal pain in the neck, innit! These days my neck starts to act up when I have to drive longer distances as well .. and longer distances over here ain't like 15 hours, haha. --> If I drive south for 1 hr, I'm in Belgium, 3-4 hours to the west and I'm in Germany. Driving 15-20 hrs to the west, I'd prolly be close to Russia, or in it, lol.
Not sure if I could drive that long anymore with my neck though .. So I feel for you, take care!!