Having vaginal discharge is a normal thing to happen to women but having a yellow discharge is abnormal and is a sign of a vaginal infection.
Another color of vaginal discharge besides yellow discharge that can indicate an infection is green.
If your vaginal discharge is green or yellow then it can indicate an infection especially if the vaginal discharge is chunky in consistency.
Normal Vaginal discharge should be clear to a milky whitish color and if it's any other color then it's most likely abnormal and you should see a doctor about it.