About a month ago I was really sick and within a couple of days later the back of my left thigh started hurting very bad it lasted for about 2 weeks then I thought it was going to go away and then they came back about a week ago and now it hurts so bad that I have a hard time walking when I lay down it hurts at first then goes away but then when I get up it hurts really bad where I can barely even get up it's the back of my thigh and it goes from my buttocks to my back of my knee is severe pain