What Causes Swelling In Lymph Nodes Along With Night Sweats In A Child?

My eight year old daughter had a swollen lymph node, that got larger and harder over the course of 18 months. ENT suggested she have it removed for biopsy. Days after surgery she had another lymph node near the site to enlarge and was very hard. After a round of steroids, over 3 weeks, it reduced in size. They biopsy came back as Non-malignant but had several CD markers that could indicate lymphoma. Since surgery she has had several more lymph nodes that became enlarged. Through CT scan we found that several lymph nodes were enlarged to 2.5cm x 3cm, 2.5cm x2cm, 2cmx2cm. She occasionally wakes at night, drenched in sweat. She has a wheeze in her chest now (over 4 weeks) and has not been sick. She is more than the normal tired when she gets out of school each day. She sleeps around 11 hours each night, so I m pretty sure she s well rested. She has been tested for every possibility that her pediatrician has been able to think of (lots of random viruses, infections) all of which have come back fine. She was referred to an infectious disease doctor, who looked at her for all of 5 minutes and stated that she looks pretty healthy let s just watch her for now. I want answers. My daughter has had swollen lymph nodes for well over 2 years now. Her pediatrician has suggested a CT scan but is reluctant to go through with it because of the increased risk of thyroid cancer later in life. I m not sure where to turn next, but I d like to know what is causing this. Thank you for any assistance or direction you can give us!!