What Causes Painful Ping Pong Ball Sized Swelling Under Right Knee?
Seek medical consultation!
Detailed Answer:
Hi and thanks for this query.
From the information you have provided, this is suggestive of a Baker's cyst. This is a fluid collection at the back of the knee. This may be caused by underlying knee problems like arthritis.
For now, I recommend that you apply ice packs, cut back on your physical activity and allow the joint to rest and take a pain medication like Tylenol. Also, it would be necessary to seek examination with your primary care physician for confirmation of diagnosis for confirmation and further treatment. If possible, please send a photo to us for inspection and more insights.
I hope this helps. I wish you well. Feel free to ask for more information an clarifications if need be. Thanks for using our services.