It could be asthma without wheezing, but it could be other things, like vocal cord dysfunction or anxiety. I very rarely wheeze, but I do cough and get short of breathe with my asthma. When I'm having asthma problems, I also tend to get very easily tired and generally feel ill.
Sometimes wheezing is not audible without a stethoscope too. The one time I had wheezing with an attack I didn't hear it, but the ER doctor did. That was quite a serious attack that kept in the hospital overnight and took a couple of weeks to recover from entirely, but there was still no wheezing that I was able to hear.
I understand that often when there is no wheeze there is a cough, but not necessarily. Sometimes a methacholine challenge is used to try to pin down the cause of tightness/shortness of breathe without wheezing. Sometimes the symptoms are clear enough without going through the methacholine challenge. My pulmonologist advised against doing a challenge test, satisfied that my symptoms are well-documented enough to rule out anything but asthma. If that is not the case though, it might be better to get a firm diagnose before starting to treat for asthma.
