Have you been to see an ENT yet?
I've had 3 Endoscopies that have all come back "normal". pH testing and Barium swallows show my acid reflux is extremely severe. I had an upper (probe above the UES) pH test last fall that is designed to measure gaseous reflux and it showed I had acid in my throat 46% of the day--even though I felt good on the day of the test. (A search of Restech will give you more information on this.) Because of my experiences with this, I don't believe in the Endoscopy as a definitive reflux test. It just shows if the acid has damaged your esophagus.
Also, scopes by my ENT showed throat inflammation. Is your throat inflammed?
The Modified Barius Swallow/ Esophagram test also showed acid coming back up to irritate my lungs and throat.
If you want confirmation on if you are having acid reflux events or not, I'd recommend further testing. For LPR, I was impressed with the Restech pH test.
From what I understand, the Domperidone is good for motility issues with your digestive system. That goes along with your work to stay regular. My GI doc wants me at 40 mg of fiber daily.
Have you had a Manometry done yet? It measures the pressure in your esophagus and LES. It would help determine if you are having any esophageal motility issues as well. I typically have the manometry in conjunction with pH testing.
Good news on your Endoscopy though.