hi. it is best if you consult with a doctor, preferably a general surgeon, for medical and physical examination. based from your description, it could be a possible cervical lymphadenopathy (inflamed lymph node) probably secondary to your recent upper respiratory tract infection. it will resolve as soon as your infection is controlled. a consult with your doctor will be of great help. further diagnostic examination such as neck ultrasound, ct-scan or x-ray and subsequent management (medical and/or surgical if indications are found) will be directed accordingly. hope this helps. good day!! ~dr.kaye