What is wrong with my knees?

Pretty much my knees are messed up, and I am not really sure why. It feels like my kneecap is rubbing me when I do anything that closed the angle in my knee or puts a lot of impact on me. (bike riding, horse back riding, rock climbing, running, climbing stairs)
I ride horses everyday, and the way my leg is positioned on horseback can be very painful. I have switched to riding with out stirrups (this makes it so there is less pressure on my knee) when I am jumping, or riding in a dressage saddle (legs almost straight). At the end of the day my knees are normally quite hot. I have been told that I have patella tendinitis in both knees and have been icing daily and wearing patella braces. My knees don't cause me as much pain anymore. My problem now is that when I am walking or running, I don't feel as much "spring" in them. It is as if it is just not physically possible for me. Which, as an athlete, is a very difficult concept.

So I guess my question is...could this all be from patella tendinitis? It gets worse when I go to MA for school...what does the cold weather do? Could this be some sort of arthritis?

I also think that my legs bow at the calf a bit abnormally..Here is a photo for you to see.

http://img.equestrianlife.com/getImage.php?type=4&member=7916&gallery=8650&img=meandwally.jpg&size=1

I know I am leaning on that leg, so that will exaggerate it a bit...but doesn't this still seem a bit much. The leg that you can see well is the knee that bothers me the most..

...What do y'all think?
this has been going on since september...