What causes the thrat to constrict and shut off breathing a bit?

Allergic?: Sudden allergic responses can cause your throat to swell and shut off breathing -- if this goes untreated and progresses to full closure, you will die. If this is happening right now, you need immediate medical attention. If this has happened in the past & you've recovered, you need to find out what food, etc you're allergic to & avoid it. See your doctor to work on this.