Hi.. While you kneel down you hurt your tendon and irritated a Bursa..a fluid filled sac located in the knee... This is the reason for your swelling and pain in the outer aspect of the knee.. Since you had pain and other knee is also hurt while kneeling down...it got inflammed and bruised when you start loading it... Don t worry... I recommend you to do Lot of icing in both knees... frequently.. Gently massage over front thigh muscle...not on the knee... slightly above the knee.. keep your knee wrapped with compression bandage... If you have any Anti inflammatory tabs that were prescribed to you before have them... As far as possible don t load your knees too much...for a while.. Hope this is helpful for you kindly revert back in case you need any further clarification in this regard...