Startles easily

My little guy startles so easily! He still displays the startle reflex a bit for no apparent reason but he is also very jumpy, obviously if there is a loud sudden noise that makes sense, but even if I touch him lightly on his arm while he's breastfeeding with his eyes closed he jumps a mile. He doesn't like to be swaddled and this startling does keep him from sleeping on his own, even in the Rock and play he'll only do one sleep cycle. In his car seat in the car or when I'm wearing him are the only times that he'll take more than a 40-minute nap during the day. I'm not worried or anything but does anyone else have a baby who seems to be extra sensitive and startled so easily?