Thanks for your question as you are facing the problem of itching and swelling and your vaginal area is very red then it is caused by vulvovaginitis and there is no chance of sexually transmitted disease.It is caused due to the overgrowth of the residing flora that is the bacteria and the fungi which are overgrowth on the vaginal area.As you feel pain at the time of touching but no pain during urination then the treatment may depend on the infection means due to which infecton you are cause with.For the process of checking the infection an internal examination and microscopic test is required for the diagnosis.because your vaginal area is swelling and is getting very red. If we look behind all this there are some other causes also which may be a part of your infection.It may be vaginal yeast infection or there must be a chances of trichomoniasis infection. But there is lesser chances of sexually transmitted disease because the infection caused on this discomfort is probably vaginal yeast infection whose chances are more than the chances of STDs. So according to me I would suggest you to consult a doctor in person near by your area.Take care