bevanoli

Hi guys, New to this forum. Ive got a 2019 5 series touring and this has happened twice in a week now. The car comes up with a Chassis warning on the Drive and when driving, every bump in the road feels as though its huge but also any small hole feels as though its a pot hole. It feels as though im driving a go kart! I turn the car off, open the door then turn it back on and it solves it... BMW want £150 just to look at it... Anyone got any ideas?!