hi, the possible causes for your problem are, -as blood supply to local organs increases in pregnancy, little friction can lead to pain and irritation, -pregnancy is a physiological immuno compromised state, so there is increase chance for vaginal infection and urinary tract infection, that may also be responsible for your symptoms. so if these symptoms are persisting you better visit gynecologist and undergo examination and urine microscopy if needed culture and sensitivity, by this primary workup you may find the cause and treatment can be taken. take care.