Dreams are like emails with attachments from my subconscious. If I don't understand them, they will come back again in some form or another.
Oftentimes the body is experiencing something and the dream is formed about it. Are you having trouble breathing during the day? Could be sleep apnea. Some people stop breathing in their sleep.
You could have yourself checked out by a sleep therapy organization but it could be expensive. Someone I know went for 8 hours and they told him yep you have some sleep apnea. No cures. Not sure it is worth it.

Maybe the clue to what it means is in you. Try meditating, sitting or laying down and count the breaths from 1-10. Then when you are relaxed have a conversation with your lungs. What are you trying to tell me then listen. And watch. Sometimes we hear things or see scenes. Another option is to focus before you go to sleep and think in my dreams I will know what it is the loss of breath is telling me.

I could give you ideas but that would take away the spontaneity. Feel free to followup with another post or PM.