Think nine inches long and cylindrical. Then get your mind out of the gutter and up to the gullet. The esophagus is a tube that connects your throat to your stomach, pushing food on its way. Some easy-to-swallow lingo:

Esophagitis will give you a pain in the neck or chest just after swallowing (itis means inflamed). In HIVers, especially those with CD4 counts below 100, the usual cause is the yeast infection Candida. If antifungal treatment doesn’t help, an upper endoscopy (EGD) can slide a camera down the hatch to see what’s going on (and take biopsies). It finds esophageal pests, both infectious (like herpes and CMV—treated with antivirals) and noninfectious (like an ulcer).

GERD (gastroesophageal reflux disease) is a $10 word for heartburn: Stomach contents leap back up into the esophagus, a common problem even in neggies. It hurts—and scarfing large meals; lying down right after eating; smoking; or eating mints, chocolate or spicy foods make it worse. If the urge to GERD hits more than twice a week, lasts for hours or doesn’t respond to over-the-counter treatment like antacids, tell your doctor. HIVers with lipodystrophy’s extra belly fat may be especially vulnerable, because that can increase pressure and reflux. The best treatment involves stomach-acid combatants (Prilosec and its cousins), but first make sure your HIV meds play well with them.