Symptoms of hernia include incarceration?

Not exactly: I would think of incarceration as a complication of a hernia rather than a symptom. A hernia is said to be incarcerated if something is stuck within it precluding it from being reducible. This is typically fat but can be a loop of intestine. If it is intestine, this can lead to nausea, vomiting, distention, and severe pain--this is a surgical emergency.

Complication : Incarceration is a complication of a hernia. It means that you can not push it in anymore. It stays out.