Lump on neck after traveling in a car for a long time? Overactive thyroid in family.?

The first time this happened was after a 6 hour car ride. Now that I've done some longer road trips, I've gotten the same lump during or after the trip.

It is on the right side of my neck, just a hair back from the center (of the side of the neck). What is this??

I do have a history of overactive thyroid in my family, I don't know if this is related.

I think the thyroid is in the center of the neck, but if it's just to the side of the center, it could still be your thyroid. I'd have it checked out by a doctor since it is in your family history. There are also lymph nodes in your neck too, it could be your body getting overly tired. But have it checked--it's so hard to know what it could be.