Noticed Small Swelling In Neck Without Pain. Is It Due To Infection Or Anxiety?

Question : i can notice a small swelling behind my right ear on the neck without pain..since two days i can also notice mild pain in the middle of the neck backside. I checked with two Drs and no one is giving me any proper reply...some says its an infection and your body is fighting...one said its neck muscle spasm..its almost 2 months. I had by blood test done which include, Thyroid, Blood CP with ESR and HIV... All ok not abnormality...Someone said its because of anxiety...i used to have mild depression but no more since two years...i am very over sensitive...Please advise :(

It's a size less then half inch approx. Spreader within Half inch like pimple but it's not clearly visible and need to press the area to feel it. I've noticed since 1 month.
It's changes the size but maximum less then half inch.
No weight loss at all. No Cough.

I forgot to tell you that I regularly do brisk walk very hard One and also do started light exercise by keeping 2 kg dumbles and bend towards both sides Simaltanously. SInce last two days I am also having difficulty moving my neck especially towards right side. However I am not doing exercise except walk. No difference in stamina. Like I did 7 kms day before yesterday.

I don't have my blood reports right now. But ESR was 11 mm
WBC was 6.7, palates were 180x

Remaining were within the range. My GP said its muscle spasm not lymph nod.