What could a pea sized lump that moves on top of jaw?

A small, pea-sized lump that moves on top of the jaw is likely to be a lymph node. Lymph nodes are small, bean-shaped structures that are part of the body's immune system. They are located throughout the body, including the neck, armpits, and groin. When the immune system is fighting an infection, the lymph nodes can become enlarged and tender. This is because they are producing white blood cells, which help to fight off infection.

In most cases, swollen lymph nodes are not a cause for concern and will return to normal size once the infection has cleared. However, if you have a lump on your jaw that is growing rapidly, is causing pain or tenderness, or is accompanied by other symptoms such as fever, weight loss, or night sweats, it is important to see a doctor. These symptoms could be a sign of a more serious underlying condition, such as cancer.

Your doctor will be able to examine the lump and determine if it is a lymph node or something else. If necessary, they may also order tests such as a biopsy or an ultrasound to rule out any other causes.