leg pain that alternates between legs

For awhile now I've been having leg pain.  It's like an ache on the back of my leg right above my knee, lower calf.  It alternates between my legs as well.  Sometimes its painful to walk.  One day my right leg will hurt, the next day it will be my left.  It seems like it is better with rest or at least its not noticeable when I get up after having my legs stretched out in front of me but its not long before it starts hurting again.  If I sit with my legs crossed or indian style it hurts when I get up.  It almost feels like I'm sore after a hard workout.  I've been to the doctor and he just seems to think I pulled a muscle and prescribed me a inflammatory medicine.  I sit at a desk all day so I'm sure that's not helpful.  This has been going on for about 6 months.  I'm 34 years old and I'm tired of feeling like I'm 80!  Any advice for me or similiar experiences?

[shanni77]

I forgot to mention sometimes this pain moves around my legs. like all of a sudden i get a cramp in the top part of my leg.

[Londres70]

Any imaging done of your legs?  Any vascular studies done of your legs?  

It is apparent more needs to be investigated especially since this isn't responding to the anti-inflammatories.