Got ultrasound for neck lymph node. They could not find it. Is this common or something I should rejoice in? Not sure if I should get another u/s.

Reactive Lymph node. Depending on how long you've been having the symptoms of cough, itchiness, chest pain you may have developed lymph nodes in response to anfectious or allergic process. This is a normal response in such situations and lymph nodes can disappear when symptoms resolve. Followup with your doctor if no change in symptoms , or you develop weight loss, night sweats or cough with bloody phlegm.