Zulqarnain

Hi, I have got bmw 5 series 63 plate with 161k miles. Yesterday I got car engine oil and filter changed and soon after that, car starting making noise from engine. I took it to few garages today and they all saying timing chain needs replacing. I'm struggling to understand there was no noise or problem like this before yesterday before car was serviced. What really happened within an hour? Is it actually a timing chain or can be something else ? Any advice or comments ? Many thanks