Hi Larz and Welcome to the HealingWell Cardiovascular forum!!
I'm not a Dr., but if you have seen one and he/or she feels that it wasn't anything to worry about and you are at the end of a cold? I'm going to 'guess' it could be some type of muscle spasm-perhaps in response to the end of your cold.
Other than that, it's not anything I've ever come across before, not that that means anything as I said I'm no expert! Perhaps one of the other members have had something like this and could give you more of an answer! Anyone??
Have you ever had any cardiovascular event before? If it continues to bother you, I would re bring this up to your Dr. and at the very least ask them for an opinion on what's causing this.
Best of luck to you! Hugs, Teri