I was on my way home from work and as I stopped at a junction I heard a loud knock coming from the rear end of the car and all of a sudden the car was not able to move forward, as if the parking brake had been engaged. I inched my way to the side of the road by letting the car roll forward (in neutral) and I tried accelerating a couple of times. After a while the car was able to move again and when I got home, I attempted to reverse but the car was struggling to move, just like how it was when the car couldn't move forward. I decided to just back up anyway because I was in a dead end and it budged after a couple of attempts. I decided to drive around the neighbourhood just to make sure everything is fine but now there's this knocking sound coming from the rear end of the car every 5 seconds or so. The parking brake was stiffer than usual when the car couldn't move but now it definitely feels a lot looser. Should I drive the car to a workshop to get it checked or get it towed to the workshop?