My child has a cyst in the hollow area above the sternal notch I believe. In the middle dip area above where the clavicles meet at the very top of the chest! Lower then the thyroid in the neck . I took her to urgent care because her dr is out of town until next week. The dr said it was too low to be the thyroid and not an area where there is anything! He said it feels like a cyst just floating there. When she yells or coughs I see it pop out under the skin. What Could this be?