### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
I have had problems for the last few months with swelling and pain when I move in my right knee. A doctor told me that it looked like arthritis in the knee. Yesterday, all of the sudden I had great pain while walking and when I got home, I noticed that there was a protrusion on the outside of my knee like a lump which was hard. The lump itself is not painful, but my leg aches and it is still very painful when I bend my knee. What I am wondering is this just another aspect of the arthritis, or should I have my knee looked at. Thank you for your advice Kathy

### output:

Brief answer:See detailed answer. Detailed Answer:Warm Welcome. I appreciate your trust in Chat Doctor and assure you are on best portal on the globe for expert online medical services. I have thoroughly reviewed health query you raised, and well realize all of those concerns. Being your physician, I will take care all of them today and will extend my expertise to solve the problems. Based on what you said, knee lump may be due to arthritis, infection or bakers cyst. You are advised to see your nearby orthopedic. If I were your treating physician, I would first order an x-ray, took a synovial fluid sample for its detailed examination and an ultrasound scan for lump. Once the cause is pinpointed, a detailed management will be devised for you. Until then, you may take tab. Naproxen 20 mg once daily for pain relief. Hope I ad Chat Doctor.  Let me know if you have further questions. I will be more than happy to clear any doubts. Keep a follow-up to see how you're doing. Regards!