Understood Ur suffering.
As u r saying,It's just HA only,¬ releived by any medicines,Can I know what medicines u have used?
In Your case HA can be due to Ur work stress/Frequent travelling,Irregular diet.
That's why,may be doctors guessed that it might be due to Gastric origin.But as u r saying no gastric related complaints u have,U can try Homeopathy .where Disease will be treated by symptoms basis but not with Tag of complaint.So,Based on Ur peculiar/Individual symptoms,Medicine will be given by understanding origin/Location/Intensity/petiodicity&all symptoms.
&No side effects at All.
Consult any better Homeopath nearby u.All the Best.
Next Steps
Before consulting Homeopath,U need to have idea abt Ur complaint .like mostly at what time u r getting? Location of Pain/Type of pain/Any associated complaint along with HA..what are the causes/Triggering factors&what are the releiving factors(other than medicine)..eg..sleep/Eating/Warm application/Warm tea /Pressure etc.