the cables were chewed up from his dog and all but i took it to a bike shop and they replaced all of it and the bike was fixed.
today i took it on a ride and since i am new with riding a bike with front shifting gears; i started messing with them more than usual and now the my gears wont shift... its stuck on gear 2 ( the bike has 3 shifting gears)
since you're bike seems like it's either from early 2000's, It's very possible that you shifters grease is hardening up pretty bad. ...... One way to verify that it's the front shifter is to undo the cable off the front derailleur. .. check if the front shifter clicks 1-3/3-1.. if it does not then that's the problem, stuck shifters can result from the old grease hardening up.
You can try WD-40 (a degreaser/ water displacement) on the front shifter .. give it a soaking.. try clicking it.. and work it's way
keep trying it repeatedly til it works loose ..... try this for a good 5-10mins or until it works loose.. just clicking away.. to get the WD-40 to work the grease loose.
worse case take off the shifter.... remove the the covers of the shifter.. make sure it WD-40 Soaks.. and then rinse.. then re-grease with superlube ..
I rescued a bit of older mountain shifters using WD-40 and eventually re-greasing them.
Note, your rear shifter might also have issues soon because of the hardening grease too..
after you get the shifter working go through the front derailleur adjustment that painkiller provided.
If you don't regrease it after WD-40, be sure to apply somekind of lube like triflow or some kind of chain lube...