It looks like end of my stair railing was attached to the wall with four small nails, and it has come off. I tried pushing it back to the wall, but cannot get it to align to the original position (holes are a little below). I was not able to have it align even after applying the downward pressure on the railing. Can you suggest the best way to fix this?
I don't think your railing was installed correctly in the first place, and suspect the lower end-post may have tilted slightly, so resulting in such a huge gap on the upper end. As the railing assembly has deformed, it requires quite an effort to correct it, which is a job for professionals. Please call a carpenter to assess the situation, cause of the deformation, and please come back to let us know.