Distended Neck Veins

Last night, as I was lying down, I felt pressure in my ears, head, and neck (here, it was a bit of a tightening sensation down both sides). When I touched my neck, I could feel the veins bulging from under the skin. It was one vein on each side, both most visible in the hollow above my clavicle and then up the neck extending toward the jaw. It was worst when I lay flat on my back, but I could still see them when my head was elevated a bit---just up on two pillows. They’re not visible when I’m sitting or standing. When I sit or stand, the pressure in my head and ears lessens substantially. I cannot tell if what I’m feeling is a rush of blood to my head or related to my sinuses. I have bad allergies for which I recently visited an ENT—he prescribed Nasonex because of the abnormal mucous presence in my nose/sinuses. I just started the spray yesterday. He also felt my neck for lymph nodes—all were within normal range; he wasn’t concerned. I’d asked about when I push on the one lymph node, that I could see the blood in the aforementioned vein on the left side of my neck swell with blood even when I stand. He said I’m thin and the node just happens to be there, it’s unconnected to the vein and if I were to push like that on anyone, it would cause a swelling vein.
   I have been having heart palpitations since November. About a month ago, they ran a full blood workup, did a chest X-ray, three EKGs, an echo, and put me on a Holter Monitor. The blood tests, X-ray, EKGs, and echo all came back fine. I have a slight murmur, which no one seems concerned about—they said I have trace…something…and that it’s benign. They also said the monitor picked up PVCs, but that the structure of my heart is normal, so there is nothing to worry about. They think it’s perhaps caused by stress.
   Any insight into what might be causing my veins to bulge would be much appreciated.  I've read that this can be normal in people with thin skin when in the positions I was in, but I'm still curious.
  I'm 25 years old and otherwise healthy.  127lbs, 5'6".  On birth control pills.

[NTB]

Hi, what is your blood pressure? Yes, the pressure in your head and neck will generally be lessened when you sit up or stand... when you are upright the heart has to pump uphill.

If the veins were bulging when upright, that might be more to be concerned about.

[JessM2307]

Thanks for the reply.  My blood pressure was 113/77 when last taken.  Resting heart rate 74.