hello der Your lymph nodes play a vital role in your body's ability to fight off illness. They're scattered throughout your body to trap and destroy viruses, bacteria and other harmful organisms. In the process, the nodes closest to the infection can become sore and swollen — for instance, the lymph nodes in your neck may swell when you have a sore throat. Other nodes that commonly swell are located under your chin and in your armpits and groin. Although less well known, you also have lymph nodes in the mesentery — the thin tissue that attaches your intestine to the back of your abdominal wall. The most common cause of swollen mesenteric nodes is a viral infection, such as gastroenteritis — commonly but incorrectly known as stomach flu. consult surgeon for further evaluation and treatment.