Had a protein shake earlier (homemade with a magic bullet which causes it to be frothy for a while) and I drank it fairly quickly. Had definite sensation of fullness and needing to burp. Kinda burped but now I have some chest/stomach pain when breathing. What gives? I'm 8 months post-op.

Drank too fast?

sounds like you drank too fast, and maybe the air in the shake didn't help either.

Get up and move around, it should help.

Try to take small sips. I use a Ninja and there is foam/air...I just take it slow and let it sit a little bit. By the end 90% of the foam is gone.

Ouch! Sounds like you drank too fast! I agree with everyone else - try walking around to help move things about. I hope you feel better soon!!