How come I cough everytime I eat?

Swallowing trouble? Dysphagia (trouble swallowing) can cause problems. Uncoordinated contractions in mouth, throat, esophagus can cause pooling of material. A bunch of causes. Less likely is fistula (abnormal connection) between esophagus and trachea (windpipe). See your doc; video-esophagram or feest test can test swallowing mechanism; may be treated with rehab.
? Aspiration. Coughing is stimulated as a protective reflex to aspiration, food or fluid entering the trachea or lungs. A modified barium swallow can assess for aspiration and focus on ways of preventing this. There are other causes so it should be e.g.Dilated.