Can you tell the difference between Bv, yeast, and stis? I've been getting this whitish pale green discharge for so long I can't remember when it started. It's just slime like(not clumpy or foamy). There's no pain but occasionally, mostly at night, the top part of my vagina itches(where the pubic hair is). There is also no Oder. When it dries, it becomes a yellow stain that smells semi sour. If this has been present for many years and caused me no other symptoms, could it still be possible it's an sti?