Does anxiety/stress cause (not just worsen) reflux such as gerd or lpr? if so, why is this the case?

GERD, LPR and stress: However, certainly at age 22, you're young to get this condition. Your doctor may also check for helicobacter pylori. Dietary habits and ilfestyle (alcohol, lying down after eating, overly heavy meals may also contribute). Here;s how stress contributes-- the autonomic nervous system is over stimulated causing excess acid, relaxation of the esophageal sphincter, hypersensitivity to acid, etc.

Yes it does: Anxiety or stress causes increased production of acid in the stomach, which in turn relaxes the gastro-esophegeal sphinter causing acid reflux other wise called as gerd.