Did your doc feel the lump in your neck? Sometimes I've thought I've felt a lump that wasn't actually there... it was just me being a little overly sensitive. (1 cm = 1 inch to someone with HA.)
As for the cold, it may not be a cold. Before I was treated for LPR, I thought I got colds all the time, too. It turned out my sore throats that occasionally seemed to progress to a light cold were from LPR, post-nasal drip and (maybe) allergies.
LPR can cause post-nasal drip and ear problems. Basically the acid comes up and irritates your nasal and sinus passages, resulting in a whole lotta mucus. The mucus from your sinuses drips down and further irritates your throat. If it's allergy season, the cycle will speed up. After treatment for the LPR (and Mupirocin, a nasal antibiotic I forgot to mention), my post-nasal drip completely stopped and my "allergies" and "colds" got better.
In fact, I used to think I was always the first one to catch a cold. But I recently traveled on four planes in winter to and from places that were FULL of cold-ridden people who were literally serving me food they'd made while wiping their noses and I didn't get sick.