What can be the reason for feeling of a lump in throat and bubbles in chest?

Hi doctor,

I just had an endoscopy and colonoscopy for stomach issues and have a feeling of a lump in my throat when I lay down and breath normally and if I take a deep breath, I have bubbles in my chest. They ruled out acid reflux, GERD, and everything else and said I am perfectly healthy. But I want to see a pulmonologist. I have smoked for years, but I want to know what this could be. I had x-rays done about three months ago, and they did not see a mass in my lungs and said I sounded healthy, so I am wondering what this could be.