I Have A Medical History Of Celiac, I Have Had

I have a medical history of Celiac, I have had swelling and a lump in my right armpit. I was given antibiotics and it improved greatly. It was 95% but sometimes swells up and then goes away again. My GI doctor wants me to get an abdominal CT with contrast to rule out Lymphoma cancer. However all my blood work was normal. I don't know what to do