welcome to HCM!
Upper abdominal pain
has multiple causes but in your case what I can think of is Gastritis
or panceatitis.other symptoms which you described are due to the severe pain
itself.My advice is to get a ULTRASONOGRAPHY
done first.it will help in pointing towards the exact cause.You can take over the counter antacids and see if it gives you any relief.Once the results of USG are there then you can plan a visit to gastroenterologist.
hope this will help you!