Hey A.,
I too had this problem with my son. I took him to the doctor and he has bronchitis. I have to give him breathing treatments with a nebulizer every 4 hours. Hopefully he will grow out of it but you never know. It may sound horrifying to think that you may have to give your child breathing treatments, but there are worse things that can happen. See your family physician and he/she should be able to tell you what is wrong with your baby.
Also, I have found that the Ask A Dr. Websites are not that great. And, working in the medical field myself, half the time you will get an illness of the computer just to have your Dr. tell you that you were wrong and diagnos a different problem!!