Hi Thanks for posting on HCM The symptoms you describe sound like a respiratory tract infection.It could be causes by respiratory viral infections, bacterial infection, allergy or other respiratory pathologies like asthma.Getting an alternative for mucinex may not help.I will suggest you try the following: -Take enough fluids -Continue with mucinex -Add an anti-histamine like desloratadine -A steroid like prednisolone -A bronchodilator like salbutamol spray if obstructed/difficult breathing. -Avoid environmental irritants like dust, smoke and cold. You may then see your Doctor for a chest x-ray.From the results, more etiologic treatment may be proposed if it shows any infection.Such infections are mostly caused by respiratory viruses and symptomatic treatment will be ok.However, bacteria infection is possible and will need antibiotics. Hope this will help Best regards