I am glad you will be having the heart tests, but try not to worry. PVC's are extremely common and usually benign. I have over 15,000 per day and mine come every other heartbeat (bigeminy). I have had all of the tests and even mine are benign!
Also, you are more likely to have them when you are at rest than when your heart rate is higher. As the heart rate decreases it allows enough time for the extra contraction to jump in there. Also, when you lie down, especially on your left side, they will be much more noticeable.
Caffeine, lack of sleep and stress are all things that can aggravate them. In my case my doctor believes I had a virus attack my heart and left it a little weak, which allows the pvc's. Mine started around the time my fibro started - makes you wonder if they are both related to a virus.
It is good that your EKG was normal, when I had my first EKG in my GP's office the nurse thought the machine was broken - nope, just my weird heart!
Let us know how everything turns out.