#1
through practice i've gotten my voice to stay in tune, but it's still unpleasant. Can i change my tone or is this the one i'm stuck with?
#2
You can change the tone of your voice.

If you haven't worked on it, you are almost certainly capable of significant improvement. Get a singing teacher.

There are limits to how much you can change it, but the odds of you being close to your ceiling, without a lot of training, are miniscule.
#3
By unpleasant, do you mean it feels unpleasant hitting certain notes, or that your voice just still sounds unpleasant? It could be down to the tone and how you pronounce your vowels when singing. Generally speaking you don't really want to waste that much breath or note time on your consonants.