That sounds like a hell of a lot, but what concentration? The size of the meal will also make a difference.
I get slight burning but nothing really uncomfortable at 9x648mg/150mg capsules of Now foods Betaine HCI. I took that in two helpings, first 5 caps before and after the meal 4 caps.
That was with a very big meal that filled a large plate. I also take 2 caps of Digest Ultimate (Platinum) along with the Betaine HCI.
Therefore try splitting it up. Are you taking any water with them? Even better might be apple cider vinegar or lemon juice slightly diluted with water. Watch your teeth!
Still some minor belching though and a tiny bit of burning. I finished eating 10 mins ago.
I am expecting some Swanson Betaine/pepsin HCI early next week. A lower dose but twice the capsules and cheaper so adjusting should be easier.