8mm module in lower esophagus found from a endoscopy. I also have a hiatal hernia. Do I have cancer? I'm 23 and relatively try to be healthy.

Probably not. Especially at your age, most often these are little benign tumors, but it's your physician's job to decide. Esophageal cancers usually look nasty and a physician will be suspicious. Ask whether a biopsy was obtained. If so, chances are it will come back benign from the lab. If your physician didn't think it was worth biopsying, it's almost certainly benign.