As a eNT surgeon I can guide you on this most common reason are:
1. Infection in near by area most common being tonsil and nasopharyngeal area
2. Tuberculosis of lymph node ( so ur history of cough is not relevant here which is common in pulmonary tuberculosis in which neck swelling will not be seen)
3. Carcinoma in near by area which is also not usual in ur age
4. Localised tumour like lipoma, sarcoma
5. Localised blood collection
Most common cause in ur case is localised infection in near by area.
What’s it’s consistency and does temperature over skin is raised
Next Steps
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