This is a tikz + fancyhdr
way of getting things done. Here the text is automatically put on right of odd and left of even pages.
\documentclass[12pt,x11names,svgnames,twoside]{article}
\usepackage{tikz}
\usepackage{calc}
\usetikzlibrary{shapes.misc}
\usepackage{varwidth}
\usepackage{lipsum,fancyhdr}
\usepackage[a4paper,bindingoffset=.2in,left=1in,right=1in,top=1in,bottom=1in,headheight=\baselineskip,
headsep=9mm,footskip=13mm,showframe]{geometry}
\fancypagestyle{sideheading}{%
%% Clear all headers and footers
\fancyhf{}
%% Right headers on odd pages
\fancyhead[RO]{%
\begin{tikzpicture}[overlay,remember picture]
\node[fill=NavyBlue!50,text=white,
inner ysep=12pt, inner xsep=20pt,
rounded rectangle,
execute at begin node={\begin{varwidth}{\textheight}},%<====
execute at end node={\end{varwidth}},
rotate=90]
at ([xshift=-13mm,yshift=0mm]current page.east)
{\sffamily\nouppercase{Rotated, right margin running text which is
vertically centered and only for odd pages and this is going to be long}};
\end{tikzpicture}
}
%% Left headers on even pages
\fancyhead[LE]{%
\begin{tikzpicture}[overlay,remember picture]
\node[fill=magenta!50,text=white,
inner ysep=12pt, inner xsep=20pt,
rounded rectangle,
execute at begin node={\begin{varwidth}{\textheight}},%<====
execute at end node={\end{varwidth}},
rotate=90]
at ([xshift=13mm,yshift=0mm]current page.west)
{\sffamily\nouppercase{Rotated, right margin running text which is
vertically centered and only for even pages}};
\end{tikzpicture}
}
\renewcommand{\headrulewidth}{0pt}
\renewcommand{\footrulewidth}{0pt}
\fancyfoot[R]{\thepage}
}
% ----------------------------------------------------------------
\pagestyle{sideheading}
\begin{document}
\lipsum[1-12]
\end{document}