Hallow dear, I have understood your problem and fully empathize you. Your symptom that when the penis is fully inserted inside the vagina, you get pain. You should have mentioned where you get the pain - in the vagina or in the abdomen. This type of pain is typically felt in the lower abdomen. So I will presume that the pain is in the lower abdomen and will guide you accordingly. Such pain by and large is there either due to the infection in the pelvis or the deeply retroverted uterus. Since, you were virgin so far, the chances of chronic pelvic infection are very remote. However, if you have caught fresh infection from your husband, such pain may occur. If your uterus is deeply bending behind called as retroverted uterus, (which otherwise bends forward) the ovaries fall very low between the vagina and the rectum. Thus when inserted deep, penis presses on the ovaries causing pain the flanks. Please report to your Gynaecologist. On clinical examination, the diagnosis can be done. For pelvic infection, you may require some antibiotics with anti-inflammatory medicines. If it is deeply retroverted uterus, doctor will see whether it can be corrected manually and held in position by pessary. If it gives relief, you may require surgery for correcting the uterine position. I am sure, I have guided you properly.