Hi Lurgan. I've got exactly thye same problem like you.: similar pain to sciatica pain, but I feel it mainly on my hamstrings , but NO PAIN on my back. Everybody is telling me that is a Boulge disc on my back causing the problem. I am frustrated because for more than 2 month I am treating this pain with no results. It is very hard for me to understand how can the back to cause the pain in my leg, when I have no pain at all on my back. The explanation :"...nerve...get stuck to this sheath due to either tight muscles, scar tissues forming etc ...." sounds preaty logical to me. I am interested if there are some " experts" who agrre to this explanation ? ...and I would like to know what are the exercises I have to do to improve my conditiion? Could be this problem caused by some substances or some lack of minerals on my diet ?