 [ Symptoms ] i have pain in my knee under the knee cap the back of my knee and my thigh is this just arthritis  some times i can hardly stand i have always tucked my leg under me when i sit down i can not any more the pain is too harsh some times my thigh muscles and calf muscles hurt so bad is this all part of arthris [ Disease ] possibly but could also be due to soft tissue issues with the ligaments muscles etc there is also something called a baker is cyst that can form behind the knee that might cause these symptoms