Hi my name is Colter I'm 15 and the viola is the first instrument I've showed interest in. My parents purchased one for me and I've just started learning. I have no teacher (I know, "Worst mistake of my life").

This is my problem/concern:
Whenever I play a note that requires 2-3 fingers I can't help my fingers slightly touching the string(s) next to them. Whenever I pluck those strings (the ones my fingers are touching) they produce a horrible twangy sound. I thought that maybe I was just over analyzing because it is not frequent that your fingers stay on one string while you bow the one next to it open is it? Is this a problem? How do I fix it?

ok a violinist here, but the same generally applies i'd say. if you have your fingers on one string but are playing another (the one beside it, then you generally take your fingers off the strings. OR you learn to play your fourth finger, the pinky. on your d string there is d-open e-1st f-2nd g-3rd and then your pinky would play a, which is the next string over, they are exactly the same note, when in tune of course.(this only applies to the string above the one you are on, the higher one) so you could take your fingers off the string or play fourth finger. you know if your in tune because the two notes, 4th finger and a string would sound the same.
this is provided that your not touching the a stirng.
o dear. that was the whole point right?
make sure your fingers are nicely rounded, like an upside down horseshoe. either practice not touching the strings, or take your fingers off. thats easier.

i have the same problem! i'm playing a piece (Hoffmeister Concerto in D First Movement) and I cannot move my fingers at a fast enough pace for some double stops. I pluck the C string and alone it sounds nice but with a chord that doesnt involve C it doesn't sound to pretty. I need to work on it because I'm playing this piece for a judge and a grade. I'd suggest getting a teacher and slowing the tempo until you can master it a slower pace without the twangy sound. Then floor the tempo and play it fast. Violas tend to rush, it always works against us.