To check if your vehicle is suffering from low car brake pads problem, step on your car brakes pedal, if it is fairly low, then your car brake pads is low.
When replacing new car brake pads it is recommended to also have you’re disc be machined to have a proper alignment with your car brake pads.
The other reason of squealing noise is that, your car brake pads is vibrating at a very high frequency and is not easy to detect, you need to remove your car tire to better check your car brakes assembly where the squealing occur and check for looseness on either your car brakes pad or car brake caliper, better to check also your disc for deep grooves which resulted from contact of car brake pads and disc that produce squealing. You can also check your car brakes hardware for looseness of anti-squeal shims and anti-rattle springs. Sometimes squealing can cause by glazed pads and non-factory brake pads.
Brake squealing is not always an indication of car brakes problem, as long as your car brake pads are not too worn and your car brakes are working properly.
Local auto parts store offers available product to fix the car brakes squeal which are cheap and easy to install, you only need to ask the sales person, but having a mechanic to inspect your car brakes system can be considered but may entail additional cost.