Why do i have knee pain when i exercise or walk and then swells up?" i was swimming breastroke the other day and my knee suddenly popped out of nowhere. it started to swell and hurt severely. i am a young teenage athlete that runs and swims and i also ha

You : You need to see your doctor for an examination and testing. You will likely need a test called an MRI to check for any tears in the ligaments of your knee. If there are tears found then a surgery may be needed. For now you should rest your knee and seek medical attention. Good luck.

Need evaluation: Pain and swelling in the knee is not normal as you know. This is commonly caused by arthritis or a meniscus tear. You need an exam and and xray to start and probably an MRI to evaluate your meniscus and cartilage surfaces. See an orthopaedic surgeon for this.