Anyone else's baby a light sleeper?

Ra

My son turned 5 months today and he's such a light sleeper. We've just put him into his own room as he was storing so easy when we came to bed etc. Even in his own room just walking into the room quietly he starts moving around. When he falls asleep in the car and I lift him back into the house in the carseat he often wakes up. I also have a 3 year old at home that makes a lot of noise and a dog so it's not like he's used to a quiet environment. He never naps in the living room anymore or falls asleep in his bouncer he likes him cot. He doesn't really even like to sit and cuddle to sleep which I miss he just likes his own space to sleep. To let him sleep peacefully I put his sound machine on to drown out the noise of my toddler running around.

Lots of babies you can pick up when they are asleep. Why is my son such a light sleeper. Have I caused this?