The most common cause for feminine itching and burning is a yeast (fungal) infection, and is commonly known as thrush. To name just a few .... some medications (ie antibiotics or use of hormones), diabetes, poor diet, alcohol, and immunosuppression from illness or medications, can all cause thrush. It's also common in summer months due to overheating and clothing that doesn't allow adequate ventillation.

The second most common is vulvar dermatitis which tends to be caused by an external irritant of some kind. The vulvae are sensitive to temperature, sanitary products, soaps, powders, detergents, fabric softeners, spermicides, colored or scented toilet paper, and man made fibres used frequently in underwear. Treatment in this case is identifying and getting rid of the cause.

Psoriasis can affect the vulval area, and menopausal women are prone to a condition called Atrophic Vaginitis. This one is caused by thinning of the vaginal walls because of decreased oestrogen production in the body. Hormone creams and or pessaries are usually successful in treating this condition.

Bacterial infections can also cause the symptoms that you mention, but to diagnose those, an examination would be necessary.

I hope this has helped a bit.