shifter pedal sticking?

I have a 2007 650s with jsut about 200 miles on it. Issue was it sat for 2 years unrode till i have purchased it. Now that i am hitting the 200 mile mark, the shifter pedal is sticking, I.E. outside now stuck in 5th gear, sometimes i am able to run thru all 6 gears others it sticks in 5th but will shift to 6th, but no lower then 5th. Other times coming to a stop light shifting down to 1st it sticks in nuetral... can anyone help me out with advice is it fixable myself or does it have to go into a shop, I'm a new rider only few months of riding so far so dont know to much yet. thanks for any help.

[Sid Squid]

If you lift/drop the pedal to where it needs to go in order to reset it for the next gear, does it work properly then?
If yes then the lever's pivot is probably just a bit sticky, remove the lever, (exact details dependant on your specific lever set up, but it should be obvious how it's removed), and cleen and lubricate the pivot.
It's possible the lay up has allowed some corrosion to affect the relevant bits, the lever has a bush in its pivot, as long as you are very* careful this can be removed, corrosion cleaned from the inside of the lever's orifice and the whole lot reassembled.

This is not the only possible problem but it's the most common, and it's and easy to do, so as a first go I heartily recommend it.

*I mean this, the bush is not available seperately - don't break it.

Yes it moves properly until its stuck in 5th gear then it wont move in the down shifting motion at all just up toward 6th gear. I will try that and see if it helps thanks a lot for the advice. Just went to try and get it out of 5th gear few minutes ago still stuck but moving up and down now just not shifting.