Brief Answer:
FNAC

Detailed Answer:
Welcome to Healthcaremagic.
Hi, I am Dr Anshul Varshney , I have read your query in detail , I understand your concern.

Lymph nodes in this area can be because of:
1. Reactive Lymphadenitis
2. Tuberculosis.
3. Simple Cyst

However, they need to be co related clinically before FNAC/Biopsy is performed.

Weight loss, fever, cough of long duration associated with such mass in neck can point towards tuberculosis, lymphoma.

If you had any preceding fever, sore throat this can be Reactive Lymphadenitis.

You would need a FNAC of the lymph node to rule out the etiology.

Also following investigations would be required:

1.     Hemogram
2.     ESR
3.     Chest Xray.

This is my personal opinion based on details available here. If you still have any other query, you may please ask me.
Stay Healthy.
Dr Anshul Varshney , MD

---