Lump in subracalvicular region

Hi, 

Sorry about the typo!! Supraclavicular!! 

I really am looking for some advice and what to ask my GP. My left lymph node is swollen/puffy and I have found a small hard lump that sort of pops in and out when pressed. It doesn't move around the area- it almost feels like moving a marble between two fingers. 
I saw my GP on Monday and she did blood tests that day. The results are as follows;

ESR fine

TSH fine

Liver function fine

i am waiting till later today to find out about the CRP levels. 
I have just finished 6 months treatment of cyclosporine which is an immunosuppressant therapy. I have a diagnosis of Rhuematoid arthritis. 
I have just turned 40. I am worried that I have lymphoma. 
 

Has anyone any advice please? If my other bloods come back fine, should I ask for ultrasound/imagining etc? 
 

Thank  you .

  • Little update- have spoken to GP receptionist who has passed on that my CRP level is 12- normal range is 0-5. GP has prescribed antibiotics and wants to speak to me on Monday once the course is finished. 
    I really don't want to take antibiotics- I don't feel ill or feel like I have an infection. ‍♀️