What would be a reason someone can't burp? and is the condition treatable?

Esophageal spasm: This may be related to an inability of the lower esophagus to relax and let air out when you burp. You should see a gastroenterologist to evaluate and treat you.

Why doe one need to?: The need to burp may be related to symptoms of abd bloating, chest tightness, abd pain, nausea, heartburn. One needs to describe the underlying symptom causing the need to burp in order to get proper relief of the sensation of the need to burp. If one just wants to burp for fun as some teens do, then try drinking carbonated drinks, e.g. Sodas.