Right gland under my jaw line?

I had very bad tonsillitis back in december and couldn't move out of bed for about 2 weeks. Since then, my right gland has been on and off swollen. I got tested for glandular fever but it came back negative. Right now, the right side of my neck almost feels like a numb ache and my ear hurts also. I find I get sore throats or a phlegmy throat a lot and it often comes with a blocked nose and ear aches or blockage. I'm beginning to think it could be allergies because when I cuddle my cat 10 minutes later I feel all stuffy and as a result of this, get a sinus headache. My right gland will literally swell really big for 10 minutes and then go down to nothing for a few minutes then back up again, it's constant changing size all the time. It's very weird! Why would my gland change size all the time? (my left one is fine)