I have been experiencing hiccups that tighten my chest and makes it hard to breathe. what can it possibly be?

Intractable hiccups: Recurrent, intractable hiccups are usually from a problem with the phrenic nerve or the diaphragm - either with scar tissue, infection, a mass, or an adjacent organ bothering it. See your physician, review the time course of your hiccups and include any information about events just prior to the hiccups. Your phrenic nerve starts in your neck and goes to your belly.