You just have to look at their answers to know they don't know what is causing the pain. How could they have three different reasons the same pain happens? Not to scientific if you ask me. It's also the reason going back to them is a waste of time and money. Your knees hurt because the thigh muscles tightened up to pull into your knees to cause the pains. When you sit for a while the muscles will tighten up again to cause the pain while moving keeps some stretch in the muscles to keep the pain at bay. You can sometimes get relief yourself to the muscles, other times you can nee outside help in getting the relief (just not from the medical people. When they had you do the exercises they caused the muscles to get tighter to add to your pain rather than help it). Here's the method of releasing the tightness in your thigh to see if it is going to help you or not:
Sit on a chair with your leg partially extended to where it feels comfortable. Wrap both hands around the muscle about 2 inches behind your knee. Press in with both hands and hold a firm pressure on the muscle. Now relax, take a deep breath and exhale, then remain this relaxed. After 20 seconds or so you should feel the muscle releasing. As it’s a big one it’s going to continue to do so for about a minute or so. When you no longer notice any releasing happening, slowly slide your foot back up to the chair, then release the pressure on the muscle but continue resting your foot by the chair for another 30 seconds.
When doing this press your thumbs, side by side, down fairly hard into the top of your leg for better results. You can also repeat this for added relief.
You mentioned you had hip pains while wearing the insteps. That pain would happen when the muscles in the lower back get tight, walking different would tighten them up, so they can press into the nerves leaving the spine that go to the hips to send the pains into them. Freeing up your back muscles releases the tight ones pressing into the nerves and here's how to free them up:
(do while sitting on a chair)
Place your left hand on your left leg next to your body. Place your right hand over your left shoulder, fingers over the back and the palm in the front, and firmly pull down on them and hold. After 30 seconds slowly lower your body forward and to the outside of your left leg, keeping your left arm as straight as possible. When you reach your lap remain there for another 10 seconds, then release the pressure but rest there for another 30 seconds. Then reverse your hand positions and do your right side.
For best results relax your body first by taking a deep breath and exhaling then remain this relaxed.