@Cameo, this could be a few different things that you can trouble shoot before removing the head and having a complete value job done. (That entails replacing the valves and valve guides beside a through cleaning. Other machine work may be needed).
Always remember fire, fuel and air. It turns over fine so it is not the battery or the starter. It is most likely getting enough air but check your filters just in case and ensure they are not dirty.
Now to fire; are your plugs in good shape? Fouled plugs may cause the engine to be slow to start and as they foul further will cause the engine to be sluggish. If they are bad, this will help determine what else is wrong.
Now to fuel. Are the injectors dirty? Ethanol causes a lot of fueling problems and should be treated ever so often to help clean the fuel system. I use a general injector cleaner at least every 3-4 fill ups which for me is several times a month. This is will also help clean the combustion chamber as well and get rid of carbon deposits.
I am possibly forgetting other techniques but these are good to start with. Good luck!