I have acid reflux. i'm just wondering how, exactly, this causes difficulty swallowing?

No exact answer : When reflux is severe it can come all the way up to the throat and cause irritation and swallowing difficulties. Long term reflux may cause problems in the esophagus such as strictures and swallowing difficulties. Most commonly mild reflux causes the sensation of something being stuck in the throat without there being a swallowing problem. A detailed evaluation is necessary to sort it out.

Depends: Reflux can irritate the esophagus and cause spasm which disrupts the orderly flow of food through the esophagus.It can also cause increased tightness of the upper esophageal sphincter and make it harder to move food from the throat into the esophagus.Prolonged acid exposure can cause stricture and lining changes that progress to cancer. Suggest GI or ENT evaluation if hard to swallow/freq heartbur.