Hi i am Dr Ahmed Aly thanks for using helthcaremagic site , I recommend imaging by Xray ,MRI for better evaluation , you may ask your physician for some investigations if pain is chronic or due to underlying causes like gout , arithritis , he may start with SUA , RH factor , urine analysis and even physical examination may show that you have edema or swelling around your knee that prevents it from bending properly . Anyway for now you may start icing it for the first 48 hrs ,topical gel ,advil tab twice per day after meals ,acetaminophen tab three times per day is helpful , elevating the leg and the avoidance of vigurous actions and trypsins or diclofenac is effective with the swelling and will free the joint mobility . Hope the above information helps you,Thanks for writing into healthcaremagic. Any further clarifications feel free to ask.