Before suggesting any remedy, it is necessary to confirm the diagnosis. Usually joint pain and stiffness occurring early morning or after a period of rest is considered of inflammatory cause like Rheumatoid Arthritis. But if the pain appears after some activities it is usually of degenerative cause like Osteoarthritis. Radiological studies (X-ray) and some blood tests are needed to confirm diagnosis. According to your history, it seems you are suffering from Osteoarthritis, in that case you should avoid unnecessary physical activity, restrict weight bearing and use a knee stocking while walking. You can use diclofenac gel and local heat to reduce pain. If not controlled, oral pain killer like ibuprofen may be needed for short term use. Diacerein and Glucosamine & chondroitin sulfate capsule can be tried also for 6 months. However, as you have some other chronic diseases also, you should visit your doctor for proper evaluation and treatment.