What Causes Swelling And Pulsating Pain At The Base Of Neck?

While taking a two part six hour state exam I noticed my pulse increased and my lower right side of my neck, at the base, pulsating and swollen. I have a ventricular septal defect that is can't be seen in my last echo in 2010. I'm 54 with a normal BP no chronic conditions. The area is still puffy two days later but hasn't pulsed. Feels spongy.