Swollen lymph nodes 21 year old female

8-9 months ago I noticed a swollen lymph node in my jugular area about the size of a kidney bean. I have seasonal allergies and also suffered from frequent strep throat (recently got my tonsils removed in April). A ultrasound showed the lymph node measured 1.2 x .04cm in the echogenic hilar region. After examining neck I found another bean size one on the right side of my neck. I was referred to ENT where he wasn’t concerned and my tonsils were removed. Lymph nodes are still there so we recently did a CT scan with dye that came back showing no lymphadenopathy at all. Why is the CT scan clear but I still easily feel these nodes? I have no other symptoms other than occasional allergies but they are worrying me that they are still there. They can’t be seen unless I really stretch my neck out and look for them. Sometimes my neck feels stiff but I also am always checking to feel the lymph nodes. Should I be worried even after the scans and blood work was normal?