Knee Pain After A Short Walk, Deterioration In Blood Circulation. Normal X-ray, Soft Tissues Of The Knee Affected. What Can Be Done?

I used to play badminton for 8 years and stopped since end of April because of knee pain around both knees. I saw an orthopaedic doctor with x-rays on bone knees. He said my knee was in excellent condition based on x rays. I still go to work everyday, only office work (sitting most of the time). The doctor said only soft issues around both knees were affected. The knees appear normal without swelling or bruise . After a short walk, like walking about 500 metres, there will be some pain around the knees. However, the condition disappears after sleeping. The condition is still in place from end of April to Now. Additionally, from one week, blood circulation on both foot worsen. Was it getting serious? What I should do?