Hello and welcome to Ask A Doctor service. I reviewed your query and here is my answer. That sound is called tinnitus, which can be from any cause like wax in the ear, or infection or anything. Do you have vertigo or hearing loss associated with it? Your ear examination should be done to rule out any wax or foreign body in the ear. Audiometry should be done for hear loss. Cause should be found out first but as far as treatment is concerned, treating underlying cause will improve your condition. But there is no specific treatment for tinnitus. You need to get adopted with it, or try to change your mind and ignore it. You hear it at night is because you get alone and only this sound u hear then. So use headphones or earphones at night or find a way not to concentrate on this. Hope i answer your question. Feel free to ask if you need further assistance. Thanks.