Praise told me about your thread. I'm self-taught on banjo, mandolin, and fiddle; I don't know a whole lot about the viola, but I can offer some suggestions.
1. Did you buy a shoulder rest? The idea is that the rest should sit not exactly on top of your shoulder, but on the front of it, and the idea is that the shoulder rest , the instrument and the chin rest should be high enough to occupy the space between your shoulder and your chin so that the instrument can be held comfortably by the chin. You don't really hold it with your left hand. Of course, if you are at all like me, for the next six months, you'll be afraid that you're going to drop the blasted thing, but you'll get the hang of it.
2. Bow tension: for a laugh, you should visit my thread from last week : Sometimes goes limp. You can adjust the tension on the bow, about enough to stick a pencil between the bow and the hair is about optimal for tone. You don't want to thighten the bow so much that it becomes entirely straightened out.
3. Rosin: When I get a new bow, I work the rosin in about like you would chalk up the tip on a new pool cue, and then a good amount thereafter. The problem is that rosin is gummy stuff, and when it starts gumming up on the strings, that does horrible things for the tone. So, you have to remove the rosin build up. Rubbing alcohol works, but it will ruin the finish on your instrument if it drips onto it. I ususally use one of those Scotch/3m scrub pads from the kitchen, and use it to remove the crud off the strings.
4. Your shoulder is going to hurt some, so what I did was play for a bit and then work the shoulder out a bit, until I built up to being able to play for long periods of time. Your chin and neck can get sore too if you go at it too much in one stint. Finally, if you don't get the adjustment right for the shoulder rest and chin rest, you'll get the mother of all aches in your back shoulder blade. Best advice: a little at a time and quit when you are ahead.
5. When I learned to fiddle, it helped to cheat by taping the neck of the fiddle at the second, fourth and fifth positions, like frets on the guitar, until I learned the finger positions. I used thinly sliced up electrician's tape for this and put it on the position (on the D string) at E, F# and G. The day comes, when as an act of courage, you will have to take the tape off. You'll know when that day comes!
I'm pretty tired; it has been a long day, and I've written an awful lot to you in one message. Feel free to e-mail me anytime about questions you might have...I'll be glad to offer what encouragement I can. And by the way, welcome, and enjoy your new instrument. Hardiman the Fiddler.