I am working on putting nice figures into latex from Matlab using tikz. The problem I am having is that I have a graph written on tikz (a set of continuous points of a density function) I have two vertical lines truncating this distribution. As

What I would like to do is to add a shade between those two vertical lines and I would also like to give labeling to those points on the x-axis I tried doing this
\node [blue] at (2,0) {$\circ$};
\addplot[thick, samples=50, smooth,domain=0:6,magenta, name path=three] coordinates {(2,-1)(2,3)};
\node [red] at (3,0.1) {\textbullet};
Both of which had failed
