What u have sems more likely articular cartilage affection for ur age ( chondromalacia) . Take tab dolo 650 mg when severe pain. Otherwise take tab rejoint/ savcollagen one tab twice a day x 2 months. Also see a physiotherapy doctor for learning knee exercise and rehabilitation  which will reduce ur pain and give u comfort.  Avoid sitting for long periods more than half an hour in one stretch. If unavoidable then get up every half an hour and do stretch exercise. Avoid sitting in a position with ur knee bent for more than 90 degree. If still problem persist then see an orthopaedic consultant near u.