Noise when pedalling backward/rotating wheel

My bike is making this weird noise when pedalling backwards. It also happens when the wheel rotates, but not while pedalling forward. I just had my mechanic brake system changed for a hydraulic system so at first I thought it might be something with the brakes but since it also happens while the wheel is not rotating, I doubt it. I felt like it started coming up/got worse when I rode too fast over a bump in the road that I didn’t notice Also, I noticed the mechanic has put oil on the chain while I already had squirt lube on it :3 but I don’t think that’s the cause either. I’m kind of a newb when it comes to these things, so any input is helpful!