I am not the best to diagnose these. The neck sounds like a swollen lymph, which means an aroused immune system. Strep commonly looks like this.
Immune problems frequently cause nausea.
Crohn's disease is an autoimmune disease that could cause the above, but you have not indicated any symptoms of crohn's.
If you go to a doctor, they will certainly be interested, but will first ask that you get a blood test for ESR, lymphocytes, and a strep culture.
If you have many of these nodes, it could indicate disseminated cancer so they ask for sonograms to discount this.
Lymph nodes usually don't mean any specific illness, but relate to many.