Muscle Pain behind knees.

i have pain in the muscles behind my knees. they stiffen whenever i sit for a period of time. the also ache bad during the night. the outside bone on my right knee is tender but nothing like that on the left knee. This started with sore muscles that i thought was from not being in shape and playing tennis. it has progressed to almost constant pain and stiffness. even with 800 mg ibuprofen i was up half the night in pain. if i warm up a lot i can still play tennis but it will come back worse later in the evening or next morning. i don't see any loss in muscle strenght but they are constantly sore. if it progresses as fast as it has been the last few weeks i am afraid i won't be able to walk soon. I did go to a GP and he had never heard of this. All he suggested was some blood work.

[ATCgirl]

You could have tendonitis???
It might even be a stress injury to the ligaments of your knee???

Any other symptoms you could add:
less range of motion at the knee...
increase pain in the morning and evening? (pain subsides during the day as you warm up?)

just as a precaution I would stop playing tennis

[achinglegs123]

It's not in the tendons. It is in the muscles around the knee. Also, my right calf gets sore and very weak but not all the time. I also can get severe pain in my left hip when sleeping on it at night. I have tendinitis in my wrist and this is not the same. This is stiffness and sever ache through the whole knee area in both knees.

Pain is also bad in the morning when i wake up since the knees are very stiff. I first thought arthritis but this is definitely more than joint pain.

[atonicat]

It may be a torn meniscus. I have joint stiffness in my knee as well as pain along the inner bone and a little swelling on both sides. My PM doctor thinks it's a torn meniscus because my xray showed some inflammation.

I also have the other symptoms you have. The muscle behind my knee aches and the pain is worse when I'm not moving. I thought mine was arthritis as well but the xray proved otherwise. I just had an MRI done so I'm waiting to see if I need surgery.

I have a compression brace that I wear on bad days. Which is almost everyday since my office is up a flight of stairs, which makes it hurt so bad.