Position text next to rectangle in TikZ

Question

Consider the following TikZ code:

\filldraw[fill=black!40!white,thick] (0,1.5) node[above left] {start} rectangle (3.2,2) node[below right] {end} node [midway] {cp} ;

It produces a rectangle at the required co-ordinates, with text cp inside the rectangle. I require text labels to the left and the right of the rectangle. I have attempted to produce these with the text attached to the above left and below right nodes. However, the end label is positioned slightly lower than the start label. How can I fix this, or, is there a better/easier way to position text next to rectangles. I have looked through the tutorials in the first section of the 700+ TikZ manual.

Edit: Additional information in response to percusses's answer below:

\filldraw[fill=black!40!white,thick] (0,2.5) rectangle (3.2, 3) node [midway] {cp} ;
\node[fill=black!40!white,thick,draw,minimum height=0.5cm,minimum width=3.2cm,label=0:end,label=west:start] at (0,1.5) {cp};

Note the different x positions. Your code (the second line above) places the entire structure such that start is positioned at position 0. For some reason, the structure produced by my code is shifted to the right so that it starts in the middle of the rectangle relative to yours.

Answer 1

The manual is indeed long but it's very well structured so you can skip many irrelevant parts. For this specific example, you can use a node and put labels around it.

\documentclass{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\node[fill=black!40!white,
      thick,
      draw,
      minimum height=0.5cm,
      minimum width=3.2cm,
      label=0:end,%< -- This uses angle zero degree on the border for the location
      label=west:start %< -- This uses an anchor of the node for the location
] at (0,1.5) {cp};
\end{tikzpicture}
\end{document}