I've been having this problem since I bought the product a few weeks ago. It randomly refuses to pair with my iPhone - doesn't appear to be any one particular headphone and happens at random. But when it does happen, rebooting the iPhone, resetting the Beats Pros, doesn't work - for example I've spent the past hour repeating different options. Nothing worked, then after closing the lid on my charging case and giving it a last go, it worked.
The buzzing sound (well more like a high pitched insect such as a mosquito) occurs when I beats pro earpiece into my ear, and is like static as I move my finger across the earpiece. At the time, the controls on the earpiece do not work.