What Causes Hyperacidity Along With Severe Pain In Abdomen Radiating To Back?

Hi, I have continuous hyperacidity and it does not seem to go away. I have taken all forms of omeprazole, different dosages and it only works for the prescribed period. Antacids also dont work for long. I have tried taking charcoal tablets but they workes for a very short time.This has gone on for more than 18months. The pain is bad and goes all the way to my back and can last all day and night even when i take anything for relief.An endoscopy was done but everything is okay. A hpylori test was done and I don t have the bacteria. At times the pain is so bad omeprazole does not help. What is the problem and how can I solve it? I don t take spicy foods or anything I suspect can trigger the symptoms.