Ok, i have a MAJOR problem with my bowing. My hand posistion is fine, though could be a little better, it's just, i sersiouly seriosuly can not keep my bow straight.
I have NO IDEA why. I've been playing the fiddle for about 4-5 years, so im not a beginner or anything. It actually physically hurts to straightened my bow, i get reeeeally bad hand cramp.
Do you guys have any solutions or excersizes to help keep my bow striaght?

First make sure your bow hold is correct. It should be very relaxed and make sure you are using your wrist and not your entire arm to bow.

It also helps me to watch myself in a mirror

I don't know how much this will help since i can't show you.. just explaining it in words.. but one thing my teacher told me last week to help keep my bowing straight is to think of moving your arm on a arch away from you as you go towards the tip. When your near the tip of your bow, your arm should be straight.

Hope that helps some..

when your bow is on the strings near the nut, ie end of an up bow, make sure you wrist is bent so that your knuckles are lower then the top of your wrist. when your tip is on the strings ie, end of a down bow make sure your knuckles are higher then your wrist.
your teacher should ahve been onto this, if you don't have one, take like one or tow lessons on it as this will seriously increase the quality of your sound. it is the bow that makse the noise after all. if you have a teacher, seriously consider finding a new one as they should have shown you this already.

I take weekly lessons, and my teacher has been on to me but we cant figure our why i can not keep my bow straight.
Its not even like its a little squint, its a LOT squint. I've being doing the correct hand posistion, and have takewn time just playing an open A, concentrating on my hand. I flex my wrist on the up bow, so my hand is kind of curled, but as soona s i move into a down bow, my whole hand crmps up, and my bow goes really squint. And i cant figure out WHY! I try and keep my hand as relaxed as possible, but my bow still zig zags all over the place.

there are some tools that you can purchase online or at a violin shop if you live near one, that actually help you bow straight. If you dont want to do that, then the next time you go out to eat like at mcdonalds or something, save the straw from the soda, and cut it into two equal halves. stick each half in an f-hole and voila. you got your own custom striaght bowing tool. just watch yourself as you bow and make sure you dont bend the straws. as for the pain, dont tense your wrist so much, bowing shouldnt hurt, just relax

Just in case, I'm sure that you are a really good fiddler.
BUT, The fact that you told us that your hand cramps every time you position your hand right is bad news.
It definitely means that you have played in a bad position for all those years, and that your hand has adapted to the position.
I suggeset that if you want to continue your good playing, then you should definitely start working now on bow positioning and posture...
I can't really say that it will be easy...because it really WILL be VERY challenging in the beginning...but i'm sure you can handle it.
Thanx.