It could also be fungal. This is just an imbalance of the flora. You should see a gynecologist and have it tested to see what medication you need. Wash all your underwear and towels in hot water with about 1/2 cup of baking soda in addition to the full measure of detergent (a lot of people don't measure). If you have athlete's foot, that needs to be treated too as it can transfer. Yeast can cause both conditions. Don't eat a lot of sugar or junk food, which feeds yeast. Eat your veggies and eat whole fruit rather than drinking juice. You can take Azo-Yeast, which is OTC.
It could just be a bacterial infection. You don't have to have sex for a bacterial infection to occur and it can usually be cleared up with antibiotics or vaginal cream