Bronchiolitis: This is a common lower respiratory tract infection in infants, typically caused by the respiratory syncytial virus (RSV). Sternal indrawing (retraction) and wheezing are classic symptoms, along with cough and sometimes fever. The age of the patient and the presentation make this a highly plausible diagnosis.

Asthma: Although less common in infants as young as 1 month, asthma can present with wheezing. However, a diagnosis of asthma at this age would require recurrent episodes of wheezing and other symptoms consistent with asthma, as well as a family history or other risk factors.
Gastroesophageal Reflux Disease (GERD): GERD can cause wheezing and respiratory symptoms in infants due to aspiration of stomach contents into the lungs or vagally mediated bronchospasm. Sternal indrawing could be seen if the infant is in distress.
Congenital Heart Disease: Certain congenital heart defects can lead to respiratory symptoms, including wheezing and sternal indrawing, due to increased pulmonary blood flow or congestion.

Foreign Body Aspiration: Although less likely in a 1-month-old due to their limited mobility and inability to pick up objects, aspiration of a foreign body can cause sudden onset of wheezing and respiratory distress. This is a medical emergency.
Pneumonia: Bacterial pneumonia can present with wheezing, although it's more commonly associated with fever, cough, and difficulty breathing. Sternal indrawing can be seen in severe cases.
Congenital Airway Anomalies: Conditions like tracheomalacia or laryngomalacia can cause wheezing and respiratory distress. These are critical to diagnose early for appropriate management.

Cystic Fibrosis: This genetic disorder can lead to respiratory symptoms, including wheezing, due to thickened mucus production. However, diagnosis at 1 month would be unusual unless there were other significant symptoms or a family history.
Primary Ciliary Dyskinesia (Kartagener Syndrome): A rare genetic disorder affecting the cilia, leading to chronic respiratory infections and symptoms like wheezing. It's very unlikely to be diagnosed at 1 month without other systemic signs.
Interstitial Lung Disease: A broad category of rare diseases affecting the lung tissue, which can cause respiratory symptoms. Diagnosis in infancy is possible but would require specific diagnostic testing and a high index of suspicion.