Check the air pressure in your tires. One side may be lower than the other. Second. Cars have self adjusting brakes. They adjust themselves when you back up and put on the brake to stop the car. If you never back up, your brakes can get out of adjustment. If that is the case, find an empty parking lot, back up about 20 times stopping the car with the brakes every time. Those are the two cheap fixes. Look at the tires, is one worn in any way more than another? Point the front wheels in the same direction. Is there any indication one wheel is not going straight ahead? Take it to a tire shop. They have seen your problem hundreds of times.
set the emergency brake
There is a brake on each wheel. The Brake Master Cylinder is located on the driver's side near the firewall.
From left to right, the pedals always go clutch, brake, accelerator regardless of which side of the car the steering wheel is on.
Assuming you have disc brakes, it could be, a sticky or stuck brake caliper on the left side brake. Grease or brake fluid on the friction surface on the left side brake. A restricted brake hose/line on the left side brake. Air in the hydraulic lines on the left side brake.
If you look on the inside of the car the brake is on your left and the gas is on your right side... And don't for get that because you will fail your driving test....
When you brake it does not take your car out of gear.
In a car with manual gearbox, the brake pedal is usually in the middle. In my first car, the accelerator was in the middle, which caused a few 'interesting' moments!In American cars with automatic transmission, the brake is on the left and the accelerator on the right. On a standard transmission (stick-shift), the brake is in the middle, with the clutch on the left and accelerator on the right.
bad or out of adjustment brake switch on the brake pedal arm
Most cars have 4 brake pads in the front two per side of the car
Have someone go in the car and press the pedal and have another look at the side thats working to determine this.
Brake pads are important to operate the car efficiently. Extra brake pads may be needed in the case that the pads currently on the car go out, and need to be fixed.
Then remove the parking brake........