Orbital mechanics is a mind fuck all in its own.
Even if you are in an identical orbit to the ISS, and 500km behind it on the orbital path, how do you catch it up?
Well, you have to slow down.
By slowing down, you put yourself in a lower orbit, which actually is a shorter orbit, which means you orbit faster, which means you catch the ISS up. You then speed back up to slow down to match the ISS orbit.
If you thrust yourself toward the ISS (ie by firing your rockets behind you), you slow down in relation to the ISS because you move yourself into a higher orbit, which is actually a longer orbit, so you take longer doing it, so the ISS speeds off into the distance.
All of that is just assuming you are matching perfect orbits and are trying to catch up with the object in front of you. You burn fuel changing orbits twice.
Changing the direction you are heading takes even more fuel. A lot more.
Neither Soyuz nor the Space Shuttle have that sort of fuel on board. Their manoeuvring systems is for small adjustments to catch up with something as described above - they depend on the big ass rocket or fuel tank they rode to orbit on in order to get them into the right orbit.