Hello and thank you for using HCM for your health issues! From the story you told us I think that you might suffer from mild distortion of lower part of vertebral column. This might happen at any circumstance, ranging from heavy duty (weight lifting, hard efforts, extreme physical activity, etc.) to sudden or unusual movements of lower joints, such as putting on the trousers or pyjamas. in these cases the ligaments and muscles holding together the spine vertebrae cannot secure these in place and the vertebral discs move very slightly out of their normal position. This shifting is very small (less than a milimetre) but enough to put pressure on the passing nerves and compresses them thus producing pain. The pain usually gets harder when moving or standing in different positions and calms down in other body positions, just as you stated. Sometimes the pain is really hard and makes it difficult or impossible to move, work or even lay in bed. I recommend you the following in order to alleviate your symptoms and get a full recovery without any medication: please repeat the following yoga positions once a day for three days. They can be found at the following link http://breakingmuscle.com/fitness/heal-your-lower-back-pain-with-these-5-yoga-poses You do not need to do these exercises professionally, just do them the best you can. Please do all the 5 exercises shown in the link above in the order they appear there. I truly believe that you will recover in a couple of days if you follow these instructions. Watch the video first and then peform the exercise. I have usedit in many patients and the results are spectacular. I hope that you will recover soon and I wish you good luck!