My ds always seems to choke while nursing. My dd never did that. My ds is a slow, bit at a time eater though. I don't have OAL but any letdown seems to make him choke. I think it's just him. He also seems to doze off while nursing and wakes up spluttering because I guess milk has poured down his throat. I guess it's a learning process for them - they're learning to suck, swallow and breathe.
About the throwing up, I'd try to burp him more frequently.
About the throwing up, I'd try to burp him more frequently.