Pain in upper abdomen and up to chest/middle back area. Took antacid and worked for 15 min then made myself throw up yellowish liquid is it acid?

It's your bile fluid. It's seems like you're dealing with acid reflux. You have to consult with you doctor about the treatment. The yellow fluid that you mentioned is your bile fluid and it basically means that your stomach is empty and now you are just left with bile secreted by the liver.