Honey, there is a natural substance that accumulates in the folds of the vagina called smegma (I know, lovely name, huh) that consists of salts, fats, oils, and water. It's in fact a protective substance. You might google "smegma" to see if that is what you are seeing. It's in the skin of the vagina almost all the time, general washing while bathing keeps the vagina as clean as it needs to be.
If you think the itching is from a yeast infection, you could try an over-the-counter product. It would be a separate issue from the moist white stuff, though, if the moist white stuff is smegma.
Well....nothing should be "itchy" down there; not normal.
It probably is a Yeast infection. You can always try something over the counter from the pharmacy and try wearing 100% cotton underwear to help control the moistness.
This could be related to something perfumed you are using, i.e. pads, tampons, lotions, soaps, irritating the area.