Thanks you, @sueinmn. Yes, I've just visited to my doctor and he ordered blood test and requested MRI for my lower back. My problem happened about a month ago. In my past life (over three decades) I've worked as a profresional chemist and engineer, whereby I spent most of that time sitting on a stool or climbing stairways and this could be causes of my problem. I just don't know. I'm fortunate and lucky to be an healty old man with no physical or health problem until now. I am presently taking only one presciption medicine and that is for my high chloresterol (it run in the family). Therefore, it very concerning to me that this happened without any cause that I can related to. My pain is numbness and tingling in my lower part of the legs (below my knees). It's a feeling like pins and needles that are poking into my extremities. I can walk for a while before I started to feel that my legs are about to collapse under me. And when this start to happen, I have to stop and rest until it go away. I will appreciate any help or advice that anyone can offer. Thank you