It could be bruised, cracked or dislocated. Best to see a doctor if the pain persists.
Sounds stupid to be asking this here, but I just fell from my bike and it's clear my right kneecap took a blow. It hurts when I run, though I can walk or do anything else with little pain, is it cracked or anything?
See a doctor my majic ball x ray machine is broke
Dear Atsuko Song,
Chances are your knee will heal okay, sounds like you are young...
But best not to take chances with your health; consider calling a hospital in your area. When I was in Seattle you could call Swedish Hospital for example, and there was always a nurse on duty who could listen to your circumstances, think of things you might not have considered, and discuss with you your options.
No one here can diagnose an unseen injury ,. If you yourself can't judge, then the logical thing to do would be to seek proper medical attention
If you just did it today, I wouldn't worry about it. You might want to ice it though to keep any swelling down. (A bag of frozen peas works great!) If it still hurting in a few days or if it swells too much see a doctor.
"It hurts when I run, though I can walk or do anything else with little pain."
Based on your statement, it is very unlikely that you have a fracture--that typically presents with significant pain and swelling.
My guess would be just tissue trauma.
As Gator Blu said, ice (20 min on, 20 min off) is a good approach. An anti-inflammatory drug and rest (at least no running) for a few days would probably be advisable. If it doesn't start to improve, see a doctor.
And of course this advice is free and is not guaranteed to be worth any more than you paid for it.
Always see a medical professional when in doubt.
it happens countless times to me after a few weeks its fine as if nothing happened to it