That is a great question and one that is best answered by your primary care doctor
or a doctor who specializes in women's health issues such as an OB/GYN. It is unclear what your age or comorbidities are, and so it is impossible to know the exact cause of your symptoms, but based upon your symptoms, the most likely reason is that you have an infection in that region. If you have an untreated UTI, it is possible that you are having symptoms related to that. If you have pain or burning with urination, that is a sign of UTI and your doctor may prescribe a short course of antibiotics to treat that. If you notice any white discharge, swelling, or worsening of the itchiness, it is possible that you have a candida infection, this is especially likely if you are pregnant or have diabetes as these patients are at a higher risk for candida infections. If this is the case, your doctor may prescribe medications to treat this. Regardless, it is best that you see a doctor who can perform the appropriate workup and decide upon the correct treatment strategy. If you notice fevers, chills, or flank pain, you should see a doctor urgently as this is a sign of worsening infection.