What Causes Swelling In The Glands At The Neck?

Hello. I ve bilateral swollen glands on the sides of my neck for about a month and a half. After 3 weeks of that I went to see my doctor, who told me not to worry about, it. Made me feel kind of like I was over-exaggerating, really. Shortly after the front-side glands also became swollen (I still have these large bulges) and my throat also hurts a little all the time now. I have no fever and I am not tired. I don t have cats. I spend time in the woods, hiking, but not a lot and I check myself for ticks. I have no pain. About 2 weeks ago I had abscess under my tooth and the dentist prescribed me penicillin (10 days/500 mg/3 times a day). I was hoping that penicillin would get rid of whatever infection was there - well it helped the abscess, but the swelling is still there. Do you have any idea as to what this can be? (I need to add that before this started I had hives for about a week, pretty bad, first time in my life)