2 months of clicking/friction feeling in both knees and occasional pain in l hip & knee. no injury. dr. says need better shoes. trust this diagnosis?

Depends: There could be many reasons for your knee pains ranging from traumatic or non-traumatic causes. You don't need to have an injury to experience the pains. Common causes include sprain, strains, bursitis, tendinitis, early arthritis/wear/tear, ligament injury or meniscus tear. Hip and foot problems, limb alignment issues, rheumatologic diseases could also cause knee pains. Seek another opinion.