I have back pain sometimes after working long hour sitting in a chair?

When you sit for an extended period of time, whether it is for work or you are driving or watching tv, you need to wake up your pelvis, re-orient your eyes, and move your neck and spine. It's like pieces of a puzzle. If you want to feel better, you have to be willing to make changes.

You may be holding your breath, furrowing your forehead, tensing your jaw, squeezing your shoulders. These are unconscious un-necessary movements. Honor your needs, and pay attention to what feels good in your body. You may benefit from doing The Feldenkrais Method®.

Yeah - that sitting thing can be a killer. Good news is - with a little inwards attention & movement, you should be able to relieve it.

One simple thing to do is to have a timer go off at least every 20 or 25 minutes. Then stand up. Ideally, if you can walk around for a minute or more - that will help offset all the "training" of muscles to keep them in the positions you do.

As Dr. Paul suggested, changing your sitting position can help - even if it's a subtle shift of moving one foot forwards as part of a change.

To help keep a spine supple - here's a move you can do at home and then do the same thing while seated once you get the hang of it:

http://gravitywerks.com/simple-differentiation/.

Also here are 7 Tips to Get You Out of Back Pain

http://gravitywerks.com/7-tips-to-get-you-out-of-back-pain/

As Corissa says, the Psoas (part of the hip flexors) is a likely candidate for this. Are you also stiff first thing in the morning? Do you walk like a 'little old lady' until it loosens up? Those are red flags for hip flexor involvement. I suggest Pigeon pose (I like this video for a in depth understanding: https://www.youtube.com/watch?v=0_zPqA65Nok ) but if that is uncomfortable, you can stretch your leg back from a half kneeling position (like you're proposing marriage). This puts less stretch on it to start, and you can balance by grabbing a chair or the wall nearby. You may have wonky balance for a day or two when you really get it open- that's your body readjusting to the proper length of the muscle and should pass quickly.

I wrote these blog posts on desk ergonomics and stretches other clients have found useful. Hope it can help you as well. https://www.mobilemontana.com/rmaphl/2017/4/5/desk-ergonomics-101/
https://www.mobilemontana.com/rmaphl/2017/4/7/stretches-for-the-desk-warrior/

Check out the book Ortho-Bionomy A Path to Self Care for simple self care options for pain relief. Available at Amazon.com or at www.luannovermyer.com

Most likely your low back pain is developed from sitting in your chair for long periods of time which is shortening your psoas muscle. Then when you stand up your psoas got used to the shorter position and won't lengthen out thus pulling on your low back and creating pain. This link will show you how to sit with proper poster to relieve low back pain. https://www.youtube.com/watch?v=fDxYqgbnNok&t=6s

Additionally I would add a psoas stretch into your daily routine. My favorite psoas stretch is a modified pigeon pose. To modify pigeon pose instead of putting your right shoulder over your right knee you should put your left shoulder over your right knee. If you feel a pinch sensation where your leg meets your torso then you know you are preforming the stretch correctly. For more helpful tips you can Visit my website - www.CorissaMassage.com Good Luck.

See your Chiropractor ASAP, change positions often, change chair type, use a standing desk that does both sit and stand.

Hi Sangching007,
You might think about replacing your chair with a yoga ball, or sit towards the front of your chair, tilt your pelvis forward, and put a lot of attention of lengthening your spine. Also, taking breaks to lie on the floor with your legs up and on the chair will relieve pressure off your lower back.