Lower leg and knee discomfort in both legs

What could this be....I am 34, somewhat active, ideal weight.  I have been having lower leg aches in both legs.  It's the knees down.  I noticed that my knees have been really sensitive.  If I bump them against something or even kneel on them they are sore.  The discomfort I am feeling is from the knees down.  It's a disomfort almost like a burning achy feeling.  I noticed also that the discomfort does not go away when my legs are elevated.  One day it was so bad that ended up taking some ibuprofen.  That did seem to help.  
If anyone has any ideas what could be going on, please let me know.

[Dr_Veena]

Hi,
      How are you? Knee pain usually results from overuse, poor form during physical activity, not warming up or cooling down, or inadequate stretching. Simple causes of knee pain often clear up on their own with self care. Being overweight can put you at greater risk for knee problems.
With the symptoms you mentioned I feel it could be tendinitis or arthritis or bursitis. Arthritis can be secondary to many diseases like rheumatoid arthritis, gout, injury, infections etc. Bursitis and tendinitis can occur due to over use and injury to the knee.

As pain subsided with ibuprofen it could be some inflammation like bursitis, arthritis or tendinitis. Take rest, elevate your limbs while sleeping, take ibuprofen if necessary. If the pain still troubles take an X-ray and visit orthopaedician for further assistance.
Take care.

[love48]

i have been having knee problems i fell down on a cement floor and the left leg started to have pain and then the right leg is following it so could this be a sympton of artiris or a fracture?