My vagina hole is suddenly expanded all the time. exactly like it expands when you are horny. it wont close up again and it hurts to walk so bad. i dont know exactly what to do?

If your genital organ is hurt when you walk, there has to be something wrong with your vagina rather than just a wide open vaginal opening (introitus). You may have a vaginal lesion such as a big cyst which causes the pain and makes the vaginal introitus opened. You should see a GYN doctor as soon as possible. In the mean time , use warm sitz bath 10-15 minutes, several times a day.