I have lower back pain from last 4 months now also my buttocks thighs and calf muscles pain and sometimes it's too serious that I can even do anything .. and also I have pain in upper back ... I did  x-ray , hla b27 test an also MRI all is fine .. my pain is very much in both butts mainly left when u press their are some points where it's like pinching pain but when I release it feel good.. and same at thighs...I am seriously in problem .. I spent alot of money on that . Please help me regarding this ..My neck also stiff sometime..I did exercise take medicine nothing is helping.