X-Ray Dependability

My doctor is concerned that I may have lymphoma, I have two swollen lymph nodes on my collar bone about the size of a marble, about 2 centimeters in diameter, and two golf ball sized lymph nodes in my neck below my ear, all are on the right side.  However, I had an x-ray and blood work and the tests have come back normal.  The only other abnormailties I've been having are weakness, tiredness, shortness of breath, and high blood pressure.  (My blood pressure normally runs low).

Something that started recently is that I've been having ridiculous acid reflux for no apparent reason.

I'm going for a CT scan of my neck today, but what I'm curious about is should my doctor have recommended a CT scan of the rest of my body, or was the x-ray conclusive enough to rule out any other swollen lymph nodes in my chest and abdomen, or will that need to be done based on the results of my neck CT scan?

[Dnmh]

Hello and welcome to the community. I'm not a doctor, and I'm learning as I go but my understanding is that x-rays do have some limitations in seeing lymph involvment. For instance - it can't see the thymus or other lymph nodes behind the sternum, therefore a CT scan will be ordered.
Generally, when trying to diagnose/rule out lymphoma, they get a good look at the lymph system to see what is enlarged then a biopsy is ordered on the largest lymph node. It must be a core or excisional biopsy because reed-sternberg cells (seen in lymphoma) are too large to fit into an FNA needle. Sometimes a Fine Needle Aspiration is used to check for malignancy, then an excisional biopsy is done to determine what the malignancy is.
Lymphma doesn't generally show up in blood work, that's why the biopsies.

Hope this answered your question, and if you have more, please post and I'll do my best to answer!
Good luck, hope it all turns out well for you!
D.