It would had been really helpful if you had shared more details about the onset, duration and progression of your symptoms and any other associated symptoms.Arthritis,meniscal tear,osteoarthritis.,bursitis,tendonitis,Bakers cyst all can cause knee pain. In mild to moderate injuries which cause knee pain the condition often heals on their own over a period of time. Give your knee rest for few days an avoid strenous activities. You may use an elastic bandage, straps if there is any swelling to add support. Take NSAIDs for pain relief. If the symptoms are severe it is best to get it evaluated by an orthopaedician. I hope you find this information useful. Keep us posted.
Take care and best luck!