There are direct tests to evaluate stomach acid output like pH capsule and more indirect ways like aminoacid deficiency, SIBO/H pylori overgrowth, indican presence as they all point to hypochlorhydria.
It is a fair assumption to say stomach acid is sufficient if additional betaine HCl cause burns. However, mechanical problems like leaky hiatal valve and ulcers (H Pylori) can cause sensitivity to additional acid (specially concentrated in a capsule) but you would have to go by how you feel.
Less aggressive approach to acidify stomach can be using ACV and lemon (if no allergy).
If you are bloated and feel weak after eating then perhaps you may be in wrong diet, have pathogen overgrowth and/or lack of digestive secretions to help digest/absorb food.