I having itching down there, but no signs of a yeast infection. what else could it be caused from?

Any irritant: Hpv, dysplasia(precancerous change), bacterial vaginosis, lichen sclerosus, genital shaving, irritation from the tissues rubbing against other tissue (obesity), several dermatologic changes. For non infectious sources a topical steroid is the treatment, for infection the appropriate antibiotic if bacterial, virus has to be addressed by immune system or aldara (imiquimod).