Possibly a gecko. They often live inside houses. Other lizards seldom do that. they can climb walls as well and often hide behind mirrors or other objects hanging on walls. Salamanders are slow. They walk, not run, and they too do not live inside people's houses because they can quickly dry up and die if they don't have access to water to soak themselves in. If you see it climbing walls, then it is almost certainly a gecko. Geckos are the only lizards that make sounds, so if you hear some strange sound, it may be made by a gecko. Geckos are harmless, and they eat insects, such as roaches.