welcome to health care magic
Regarding your throat pain..it has many causes including throat infection
profile is normal..
you did not mention about your feeding difficulties,,whether swallowing your food normally or facing any difficulties...
you have said that you barf often...whether they contain digested material or undigested food particles,,mixed with greenish tinge or not..
Before undergoing ultrasound
neck,,.consult ENT specialist
and he will suggest you what to do..
hope you understand my suggestion and answer..