Non stop pain in my leg

Hi, i am a 16 year old tennager with a really bad problem. it all started about 15 months ago when my right leg (below the knee , on the back side, i thnk its called the calf?) begins to ache and have sooo much pain u cant ven imagine. it istracts me from my school work. it distracts me during school in classes as well.

now having this problem for a while now i have figured out some methods to heal it temporarily (maybe an hour)

1. i have to have the leg laying down..( like laying on a bed, it is laying straight) , or putting it up onto something so it is straight laying up...that will heal it temporarily as i said.

now i have went to many many maany doctors. i have done x rays, MRI, i even took a test with the thing they use for pregnant ppl. it was used for me to see if there were any blood clots.

No doctors can find anything and ill tell u...its not in my head, it really hurts me...

now heres the thing..i also found out that it happens when i sit down. when i sit down, for example in class, i sit down normally and the pressure of my leg going against the tip of the chair puts pressure on my thigh, then the pain in my thigh moves down to where i explained before.

some people i asked say it might have to do with ur blood not circulating enough...i try to strech and all but i seriously dont think there is a cure for this thing because once i heal it,  i just keeps coming back!

honestly i dont know wat to do anymore and i cant be stuck with this for the rest of my life or i will not function properly. it is really changing my life and my mood.

i can go on and on and tell u so much about this problem but i dont want to waste ur time. so if any...i mean ANY doctor on this website knows wat to do for me i beg of u to please feel my pain and help me out.

thank you