What Causes Headache And Difficulty Breathing?

my 9 year old complains of headaches (frontal) at least 4 times a week, nausea at least 5 to 6 times per week sometimes with vomiting, and a new symptom since last week complaining many times per day that she is unable to breathe. I sat in an er for 2 hours on Friday, and once we got there, she was fine with no symptoms and we were told by the Dr. that she was the healthiest child she had seen all day. We have had Ct scans and MRI s of the brain with all normal results, she does wear glasses with a dx of lazy eye. Thank you