Is he star gazing? Or somewhat twisting his body in odd ways? Or both at the same time?
Well, what I was thinking that he may be wanting to mate, since males will refuse meals during breeding seasons which is coming up very soon. Some BPs can be finicky eaters, and a lot of the time the will go off feed for no reason at all. Your husbandry seems just fine, and I don't think anything is wrong with it at all. BPs can be easily stressed for a numerous amount of reasons, but it seems that your BP has no reason to be stressed. Also, when snakes are fed small meals, they will roam around the enclosure looking for more to eat. If you are feeding him a rodent about the same size as the middle part of his body, I dont see how he could possibly be searching for food.