You told me before my new PVCs could be caused by Coronary Artery Disease (CAD). I still think it could be stress or my back (I had steroid shots for a slipped disk) since all my blood work was normal.
Sometimes, investigating a situation like yours is like a murder mystery. Your PVCs are a clue, and the usual suspects are being eliminated as the search for an answer moves forward. Your back problems are confusing the situation, but are VERY unlikely to have anything to do with your heart. As the detective on your case I would put this clue aside.
This is what you know thus far: You have normal blood levels and not enough stress/lack of sleep. You also know that your heart function has not been affected. This however does not eliminate coronary artery disease.
While it is possible you have had PVCs for a long time and you just were not aware of them, this is also very unlikely. This means they are a new symptom and something caused them to happen. Under my care, the next step would be to analyze them further to make sure that’s all they are, and to continue look for a cause. In your case I stand by my original recommendations, check your rhythm out further with a Holter monitor and make sure your coronaries are OK.
If these next steps don’t provide a final answer, dangerous consequences will have been eliminated, at which point I’d join your FD and tell you not to worry. Of course you are not my patient, and you need to make up your own mind. This advice is meant to help you do so, using logical steps to a logical conclusion!
Hope this helps,