When I lie down on my right side at night i can feel a large lump in my jugular vein on the right side of my neck. I looked at it with a mirror whilst lying down and it is very noticeable that there is a lump sticking out of the vein. However, the lump disappears when I stand up or am sitting down and there is no lump on the other side. Does anyone having ideas what this lump could be? Thanks