Retracted testicles can occur when it's cold. Is this happening all the time? Is there anything that is happening before you notice this sensation?

Your scrotum is actually a very interesting organ. Your testicles are supposed to be kept at a temperature of a few degrees below your body temperature. So, when it's hot, the muscles in your scrotum relax to get them as far away from the body as possible. When it's cold, the scrotum tightens to maintain an ideal temperature for your testicles. As long as it is pain-free and comfortable, you have nothing to worry about.

no its only sometimes,the only thing ive noticed before this is that sometimes i have erections all night until i wake up....like 8/9 hours or so.... and no i dont take anything like viagra or anything.could it be because im a teen? or is this not natural at all?

totally natural. It gets less frequent as you get older.