Why is there a rumbling in my ear?

Yesterday, I realized my ears had some excess earwax and was oily, so while I was taking a shower I let the water come directly into my ear. After I dried my ears with my towel, it felt like there was water in my ear. I was too lazy to put more water in and try to get it out that way, so I just slept on that side to try to make it drain out. This morning, the feeling was not there any more, but when I move my head far back and forth, I hear this weird rumbling or fluttering sound. There is no pain. What could it be? Do I need to see a doctor? What should I do to get rid of this?