What would you give a 4 month for a cough?

My baby recently contracted a cough and has been sneezing. This has prob. been going on for about 4 days. Yesterday he had an apt. and had to get his immunizations, while there the dr. said that he was a little congested but she did not pre-scribe anything for him. Maybe his cough isn't as bad as I think but I just hate for him to be coughing and sneezing all the time. Is there anything OTC that you would recomnend and how do I know if he needs to go to the emergency room. He is breathing fine and does not have anything in his chest, it just minor nasal congestion but as a first time parent I am worried.