What Causes Knee Pain While MRI Reports Are Normal?

hi sir.i am of the athletic.and i will do 10,000 sikps in 1 hr.but i had injury my knee.i dont know wher the injury is ther in my right knee but the symtoms are 1.when i am folding and sitting down for some time,after standing the pain is very much and after some few sec...pain is going.2.when i am running also some pain is comming. this is my problem.pain is from 9months.the MRI report of knee is also normal.