What Causes The Feeling Of Obstruction In Throat?

I have this feeling in my throat like some food or something similar is stuck in there. It has been almost 3 years since this started. Whenever I swallow, it feels as if this obstruction tries to go down my throat, but it just returns to its previous position. There is no pain, just a constant feeling of something being stuck in my throat, all day. Also, lately when breathing, it feels as if whatever is there, has been blocking my airway slightly. Not all of the time, just periodically. I have been to a local ENT and he put a little camera up through my nose and looked down into my throat and said I had some slight bronchitis and gave me some antibiotics and sent me on my way. That didn t help at all. I eventually saw another doctor and was suggested to get a barium swallow and a sleep study. Neither found anything wrong with me and I m back at square one with no one being able to find out what s wrong or what to do next. Please help.