What would cause the sudden appearance of a large vein running from my belly button to just under breast area in the mid torso appeared today no trama to the body

There . There is a structure called the umbilical vein that is left over from fetal life (in the uterus) that can open back up in adults who have certain types of liver disease. When this happens, it can cause large veins on the abdominal wall like you've described. Usually, this happens slowly over a long period, but there are exceptions. One can also develop enlarged veins on the chest or abdomen if there are blockages in the normal venous channels. This, in turn, can be the result of blood clots or structures than press on the normal veins and close them. It would probably be a good idea for you to see a doctor about this, especially if you have a history of liver disease, blood clots, or the use of oral contraceptives (which can cause blood clots). You may need some blood tests and/or ultrasound studies of the abdomen and/or legs.
See doctor . Some veins can appear suddenly and be nothing to worry about, but if you have not had a physical for awhile with a blood work up, it would be good to get one. Do you have any abdominal( belly) distention? Swelling? He may want to look at your liver blood values. Also, look for internal medicine doctor, here on health tap.