Yeah Grondar, I am lucky enough to have all kinds of stretchmarks. It is possible to get them from gaining muscle fast because I did- I have bright red ones still in my armpits/near my chest and arms. I also have a strange one in the middle of my back that is pretty hidden by now, but it is just 1 jagged horizontal one right on my spine. Also, I have tons of old marks from when I was fat in high school all over my thighs and butt. The most noticeable of mine are on my hips. I had love handles bad, and even now that they are mostly gone, I still see big wide red stretch marks there.
Shitty genetics
I think I'm going to look into this Mederma stuff..