Thanks for this interesting question. There are several different things that readily come to mind, but it is important that you speak with your doctor
. One of them, as you suggest is a lymph node, as swollen lymph nodes can be quite common and occur in the head and neck. They can feel tender in some cases, and are often present in response to some sort of infection or other problem. Another common thing that can happen in this area involves some of the different responses that can happen either to nerves or to the muscles of this area of the face. There are many important nerves that run through this area, and these can become inflamed or hyperactive for a number of different reasons, as can the muscles in this region. If you have had some recent head and neck trauma, this could be more likely. There are quite a few other options as well, including pain that is referred from a different body part such as ear pain
or even pain from your jaw. Given that there are so many potential causes and explanations of this pain, speaking with your doctor is the best thing to do to make sure that you are healthy and that this is not something serious.