Hip and Knee pain unsolved, still bothering me

Patient: A bout 2 years ago, I went to a specialist for my severe hip and knee pain. The doctor had no answers for me after x-rays, ultrasounds, MRI and general manipulation/mobility tests. The doctor briefly said something along the lines of there is surgery but it would be more harm than good. I didn’t ask him about what he meant. I want to know, why might he say that in passing conversation, yet he couldn’t find any sign of anything in my tests and image tests? (I am a 17 year old Male.)

Symptoms: Severe hip and knee pain.