Of course studying positional chess will help you improve. The things is in middle game position, if we can't find a tactic, we will find ourselves often time clueless on what to do if we never study positional themes..Having grasp of strategy will give you an idea how to punish weak positional moves...
You don't need to study opening theory to learn positional themes in chess. Just buy a good strategy book. I suggest you try Chess Strategy for Club Players by Grooten..
...study and play positional chess?
I like studying tactics, checkmates, and simple endgames, as I believe that they are practical for my level of play. What I don't like to do is memorize chess openings, especially since players that I compete against know little opening theory, so that even the few lines I know are not used in my Live Chess games.
With that said, I do get bored when I only practice tactic, checkmate, and endgame puzzles. Would learning positional chess be of any practical value at my level, and what book(s) would you suggest that I read? Do I need to memorize opening lines to be able to play positional chess? Thank you.