If you find an answer, let me know. I have the same problem on the left side of my throat. I thought it was tonsilitis or something. I had a difficult time swallowing. I did have the EGD done, and had damage to my esophagus because of GERD, and have had surgery and medication to fix it, but I still do experience that difficulty swallowing, and it feels exactly how you described it. My thyroid levels are also fine, and I have even had a laryngoscopy done to see if that was a problem.