Get an MRI. In 2008, I was running twice a week for thirty minutes. Same time I was doing some spinning classes and spearfishing( long fins). I started getting some pain at the end of the 30 minutes but it was ok, then it started coming at 20,10,5 and it ended up coming up when I ran only 100meters. I could not even bend my leg for some minutes until the pain passed . The weird was that on that last stage I was taking spinning classes and overfishing for two hours without any pain. When I saw the doctor he could not believe since he was bending my leg and no pain was showing, I insisted to get an MRI . He was surprised that I had a meniscus ligament damaged that would only give me pain when running. After surgey didn't got that problem.
Now I have randomly swelling in my knees if I run or cycle. Doctor said my knee caps are worn out and I should stop jumping squatting if I don't want it to get worse.
So if it's a ligament or worn knee caps just see a doctor and get an mri. X ray most probably won't show anything . But see a doctor urgently , you might think that it is only on some activities that you have problem but can be reaching a worse stage of any hidden problem you have
Now I have randomly swelling in my knees if I run or cycle. Doctor said my knee caps are worn out and I should stop jumping squatting if I don't want it to get worse.
So if it's a ligament or worn knee caps just see a doctor and get an mri. X ray most probably won't show anything . But see a doctor urgently , you might think that it is only on some activities that you have problem but can be reaching a worse stage of any hidden problem you have