Small hard lump in neck. It as nothing.

I have a small hard painless lump on the right side of my neck. It is not visible, but can be palpated. it almost feels fixed to the hyoid bone, and moves up and down as I swallow. It has gradually gotten bigger and has been interfering with swallowing. Sometime it seems to get "caught" in the surrounding muscle when I swallow, and causes quite a bit of pain as it feels like it is pulling the muscle. I have to swallow multiple times in quick succession in order to "pop" it loose and stop the pain. I went the the ER recently for abdominal pain and asked the doctor about it. She felt my neck and said there was nothing there and when I told her to manipulate the hyoid bone from the other side to make it more prominent and be able to feel it better, she laughed and dismissed it as nothing.