What Causes Vomiting With Neck Pain In My Child?

I have a 5 year old son who has been complaining of neck pain on and off over the last 4 months. The pain causes him to vomit, he does it at school as well as at home. He has been getting a harsh cough often over the past couple of months as well . He also has had a fever that comes and goes. He is to the point that when his neck hurts he knows to stay close to the bathroom because vomiting comes next. It s becoming normal to him. Any ideas of what this could be? Every time I take him to the Dr they say he has a viral flu. I am starting to doubt that. It happens why to often. I usually wait to take him in once he gets a fever so I understand why they think that.