They're kind of stuck. They'll keep moving down your throat but that feeling means that the pill hit the walls of your esophagus when they were too dry so it's harder for the esophagus to move the pill down.
Think of it like trying to go down a water slide. If the slide is wet you don't get stuck and go very fast. If the slide is dry your skin creates friction and you go slow or get stuck. You need that lubrication of the water to go down fast.
If it's a common issue for you try taking pills with a bigger sip of water. Let the pill float in your mouth for a second in the water then swallow.