About 7 or 8 years ago or so I had an MRI that showed a herniated disk in my lower back. I have had lower back pain but not much else. I started college in August of 2007 and started carrying a backpack that is probably about 10 - 15 pounds. I walk up 3 flights of stair 3 days a week. I am 35 yrs old and here is my question. At the end of November of 2007 I started feeling a pulling in my calf in my right leg and it eventually started in my left leg as well. Can a herniated disk cause your calf muscle to feel pulled and to cause pain throughout the calf??? My dr seems stumped. Blood work is fine and my back x-rays showed the changes in the lower back as described above. I can feel a little tingling in my right foot as well and sometimes feels like there is a pinching behind my knee. The pulling only seems to happen after I get out of bed in the morning or after I have been sitting for awhile then get up to walk. Does that sound like anything more serious than just a disk problem?? Do you think the weight of my backpack is causing me problems?? Any help would be great. Thank you.