you can stretch sural triceps and iliopsoas too, they are in the same muscular chain.
Look at knee extension: is it extending completely? If not search why (is knee inflated) and treat, if yes and too much you can work on flexion muscles with isometric reinforcement.
Watch foot position while standing, if it's turning inside or outside it gives rotational problems on tibia and wrong strenght vectors on quadriceps. A podiatrist can be of good help.
A hip rotation has the same effects then stretch rotator muscles if necessary.
Check knee ligaments.
On inflammation and pain you can use ice, iontophoresis and tens. Forget ultrasouds.
Good luck and sorry for my english