Thank you for waiting.
I understand your concern.
I am very sorry for your symptoms.
Pain in the middle of abdomen can be due to a few factors.
It can be due to intestinal spasms, gas.
An infection or inflammation can cause it.
Sometimes appendicitis pain start in the middle first then it shifts to right lower part.
In that case tenderness will be in right lower portion.
Gastritis can cause pain here.
You can take omeprazole, gaviscon now.
As the pain is so severe, I would advise to have an examination by doctor in A &E.
Ultrasound / scan can be necessary.
I hope this information will be helpful.
If you have any query, please feel free to ask.
Your satisfaction is my goal.