I'm tired of painful feelings in my back. I have an office job and I think that it is the reason of these pains

Listen, what's the problem? If you're bothered by back pain or elsewhere, then I advise you to make an appointment with a doctor. In any case, you'll get expert advice and you'll know what your problem is.

I also believe that in such cases, first of all, you need to see a doctor. It can really help, because if you have something serious, then ordinary pain relievers can hardly solve the problem. If you still need to find some kind of pain reliever, then I advise you to try CBD oil, because it is at least a natural food supplement and it won't harm you.