The case of the mystery Seal

I think my child may have swallowed a seal. Whenever Henry has to cough whether to clear his throat, or if he has slight cough, he barks. Yes, like a seal. And for some time now (since he was born) he has had it. It stumps us slightly as Henry doesn't get coughing attacks, like those you see who have full blown asthma, but the sound of it is deep and guttural enough that people turned to see where the seal is. It is such a loud noise from such a small little person.
Henry hasn't been a sickly child. He's had some fevers, a couple of runny noses, two tummy flu's and that's about it. But he has never been one of those children who has perpetual runny boogies, watery eyes and coughing all the time. He's never had pneumonia or a very bad cough. However, since he started to walk and become more independent over the past 15 months, I've noticed that when he gets really active he has a tendency to make the loud seal bark sound. He may do it once or twice after running around (very physical child) but he never goes into a fit where he coughs incessantly and can't catch his breath.
We decided that we should get his chest x-rayed. On Wednesday I told Henry he was going to have a picture taken of his chest. We were going to have a picture taken so we could see what it looks like. He was completely game. We went into the the imaging room. The nurses greeted him. He smiled and coo'd (he's a full on flirt). One of the nurses picked him up and placed him on the big elevated bed attached to all these machines, quite cumbersome. He sat there in his little sneakers with his hands in his lap all ready to go. I think he was so intrigued by all the machines that he somehow did exactly what they told him to do. AMAZED! I got to stay in the room too which helped. They had him take a deep breath as they took the picture. They positioned him in a few different postures and then that was it. All done. QUICK! He was such a brave little guy. The following morning we went to his doctors office to have a look at the x-ray. The radiologist had noted a few pockets in his lunges where oxygen gets trapped. This could be part of the issue? Not sure at the moment. As the doctor has not diagnosed him with asthma or anything. It is such a weird place to be in, this not knowing. She suggested we use a nebulizer which they loaned to us for the next week to see if it changes his coughing. To see if he continues to bark. Hmmm. We decided to start tomorrow, Saturday, as I wanted us to be able to start this thing in a really relaxed environment. I hope it all goes well. It makes me a little weary doing the albuteral, as it is a stimulant, a drug. Not into drugs or any kind of medicine for that matter. But if it will help then we'll give it a try. We'll do the treatment for one week and then we go back to the doctors on Thursday. If there are no changes, I think we might go to a doctor who also has experience with homeopathy and naturopathy. Do any of you out there have any experience with albuteral and or have a child/toddler with these symptoms or with asthma in general? It would be great to get other feedback. Thanks!