I'm Not Sure Where to Post This

For the past two weeks i've had a feeling of something in my neck. Just recently I was working out and now the feeling has shifted from the right of my neck to the left of my neck. I don't understand what this is. It looks like if I press on the spot where I feel it it shifts sides. I went to the doctor about a week and a half ago, he checked me out and he said that he believes it's nothing serious, but this is freaking me out. He prescribed omeprazole 20mg #30, but it doesn't seem like it is helping. How can something move in my neck like that, and what is it?