Achy left knee that comes and goes. felt in leg.sometimes when i bend it or sit funny it hurts. no swelling or fractures. osteosarcoma? or less worse?

What workup so far?: If not yet done, need xrays of the knee, as well as a complete history and physical by your doctor. Depending on the findings, will likely have a trial of conservative treatment. Some doctors will refer to an orthopedic surgeon if conservative treatment does not work, while others will get a knee MRI (the appropriate next test after failing conservative treatment) before referring to orthopedics.