Need some advice on what to do?

If you have mis alignments in the foot, pelvis, lower spine they need to be corrected along with exercise and stretching. You can exercise forever and the use of orthotics will only support the position of the bones in the feet/ankles. If they are misaligned (subluxed) the orthotics will never correct the misalignment. The combination of misalignment in the foot and the spine/pelvis is probably causing your knee pain barring any significant knee derangement. Even if there is derangement it will only get worse if ankle and spine/pelvis alignment /function are not corrected. My advice; see a chiropractor that deals with evaluation of these areas as well as manipulation to the spine and especially the foot/ankle. Sometimes even the Tibia or Femur can misalign with rotational torsion which is a response to ankle/foot misaligned bones (usually the calcaneus or talus bones)