With the gassy pain, it is clearly trapped wind.
Avoid all fizzy drinks, sprouts, cabbage and white bread. You may be gluten intolerant.
Keep a food diary of everything that passes your lips to see if you can find a pattern when the problem is worse.
Cut out very fatty, fried and very spiced foods.
You can get renal colic with kidney problems, so do look at your urine to see if it is normal and does not smell like offal (kidneys).
Have you been tested for Helicobacter Pylori? A breath test is more accurate, sometimes a stool test is taken. Blood tests do not give accurate readings.
If your symptoms have not settled, make an appointment to see your doctor again.