My Son Is 3 And He Just Picked Up My

My son is 3 and he just picked up my cold that I had well just today when I put him to bed he woke up crying having a little bit of a hard time breathing so I gave him 2 albuterol treatments and hes back sleeping but coughing while sleeping. When he was crying he was holding his back saying ouch is this normal? Should I take him in to the ER or when should i really worry?