Your snake is not solid. Have you ever had a doctor give you a physical and thump you stomach or back making a hollow sound. Same thing, i bet.

Leave your snake be for several days and try feeding in it's tub at night without the lights on. It sound like something is stressing your snake. Check and recheck it's husbandry and try to fed again in a week. And during that week leave it alone other than checking it's tub.

There is no reason to move your snake for feeding, it is just unnecessary stress. If the previous owner didn't move it for feeding that could be the cause for not feeding. Many times a snake will like to hunt and stalk the prey and when you put it in a plain tub it feels vulnerable and gets stressed.

I would also suggest putting some cover (fake plants, driftwood, etc.) In the tub. I know it's not common practice in tubs but it may make it feel more secure and help eliminate stress.

You could also try a f/t so that you could place it in the tub and leave it without worrying about injuring your snake. That way it would be all alone and not have any stress. I would try this after another live attempt.

And don't stress yourself about the snake not eating, they can go a long time between meals.