Do fish oil capsules truly make you have more reflux (if yes, why?), or does it just seem that way because burps are fishy after you take fish oil.

Not usually.: although some people have reflux due to excessive fat in their diet, fish oil capsules are usually well-tolerated. It is unlikely that they are causing you to have acid reflux. If you have trouble with them, however, you should stop them. Good luck.

Cheap fish oil: A lot of fish oil can cause a fishy aftertaste. Some use lemon in the capsule to prevent that. Fish oil in the triglyceride form has less fish aftertaste. These are harder to find, but 1 brand in stores is Nordic Naturals. An online brand also has minimal fishy aftertaste: called Physician Recommended Nutriceuticals.