So scared have something like lung cancer, had cough for 7 weeks after cold, not easing. dr said chest and breathing ok and no other worrying symptom?

Workup: I trust you are not a smoker. This may be whooping cough -- it's up to your physician to consider a trial of antibiotics. It's worth asking whether you need a chest x-ray. That'll pick up almost all lung cancers that are big enough to give you a cough. You may also have unmasked adult-onset asthma -- a trial of an inhaled bronchodilator that helps the cough would establish the diagnosis.

MGT: Your risk for lung cancer involves a number of factors including your smoking history, chest imaging findings, and genetic predisposition. If you are experiencing a prolonged cough, a pulmonary function test and chest radiograph may help to determine the next steps. If your chest is clear on exam the likelihood of bronchitis or pneumonia is less. A virtual in box consult can also be arranged.