What Causes Swallowing Problem?

I have had swallowing problems for years. Small bits of food stick in my throat almost every time I eat. I have had multiple swallow tests, always negative. Went to a laryngologist, found no cause. Have had throat stretched twice, didn t help. I read an article about a bacteria that causes the throat to become sticky, causing food to stay in throat. Is this possible, if so how do I find out if this might be my problem. So far no mechanical reason can be found.