My hubby has heart problems and started feeling as if his heart's palpitations were felt in his left aorta....I took him to the ER and it ha been diagnosed that is related to his heart illness. He's still at the hospital as there are more tests scheduled to take place this upcoming week... :(
A throbbing in neck could be caused by some partial blockage in the vein, a main vein in the neck... I forget what that is called/named. If the condition continues it would be a good idea, I think, to have a doctor check it out. I believe a Primary Care doctor (don't need a specialist) can listen to the vein with a stethoscope and hear if there is any unusual flow noises, even if it isn't throbbing at the time of the check.
It is unlikely that you have this condition at your young age, but if symptoms continue a medical check-up should be done.