I Choke On My Saliva A Lot. I'm Usually Just

I choke on my saliva a lot. I'm usually just going about my normal day and all of a sudden I'm choking. I have to catch my breath and after swallowing, I burp a lot. It also happens when I'm asleep. I wake up gasping. I sometimes put my arms over my head to help. I keep water by my bed at night to help also. What could be causing this scary and embarrassing issue?