I too have worried that I've had this condition on multiple occasions. I noticed the throbbing when i lay down, and can see my pulse. What i try to tell myself though is that it is normal when you are thin, and laying down. I have no pain there, and i am young and do not smoke. The risk of it is very low unless you are older and a smoker. If your doctor has examined you and you do in fact have it, they should be able to feel a lump. So try to take your doctor's word for it even though i know it is so hard to do.