Strange noise from a lexus rx300

I have a 2003 RX300. Recently, during the previous cold spell, after backing out from my garage and moving slowly forward for some 20 yards, I began to hear a strange noise on my right (can’t pinpoint the source), like that generated by blowing wind across the bottle of an empty bottle. When I stepped on the brake, the noise became slightly more pronounced. After that, it’s gone and I remained good for the rest of the day. I’ve checked with two mechanics. One asked me to leave the car with him (which I haven’t been able to do). The other said he wouldn’t be worried about it. Now the problem is back every now and then. So what seems to be the problem? Thank you for helping me out.

Here’s a guess - might the brakes need replacement, and a wear indicator is rubbing against the disc?