Had a similar problem. I went to the doctor, and he said it was a trapped nerve in my spine.Had a course of anti-inflamatory drugs, and it's better now. Would advise going to the doctor.xx
Standing too much? If so those supportive tights can help (not necessarily granny looking!). I've had that in the past esp at night and found that although it goes against your instincts finding a comfy position, massaging them a bit and staying as still as possible makes them relax. You'll feel like wriggling them around but honestly that makes it worse.