Assuming there’s no previous trauma (ie. fracture), it's highly unlikely to be arthritis. Arthritis is usually from wear and tear, so usually an older patient would get it. Post-traumatic arthritis can happen, but only if there’s a history of trauma.
At your age group and from what you’ve written, Runner’s Knee would be one of the more common problems. A lot of times there’s a combination of some tendinitis as well, so the pain may not totally go away even at rest.
There are many causes of knee pain, and u would need a thorough knee examination to identify the location and nature of the problem. Tendinitis, meniscal injuries, cartilage injuries, patellofemoral pathology etc can all cause pain. An MRI would also usually be indicated. It would help to exclude other potential injuries. Hope this has been useful!
Dr Sean Ng
