Pro's and Con's of riding trackwork

Ok so I have just started riding trackwork

And my back is killing me!!! My muscles don't understand why they are hurting on a horse HHAHAHAHA!!!!!!

So,

1: has anyone got some exercises to do at home to help?

2: how will this affect everyday riding for me and importantly my jumping position?

Also feel free to add any pros and cons of riding trackwork that you can think of.....
Aside from those horribly early mornings ;)

Yes! There are a few ways to deal with the thigh muscle building issues.
The simplest and least expensive is this: Go to Walmart, or any exercise-equipment store, and get one of those large exercise balls. The usually blue-colored air-filled ones that look as if you could ride it.
Once you have it blown-up (usually comes deflated) Find a comfortable way to sit on a chair, and place the ball between you knee-thigh area, squeeze, hold, release, repeat. Hold for 3 to 10 seconds, depending on your fitness or pain level (shouldn't hurt a whole lot!) do the squeeze 5-12 times in a row, stop.Wait 30 seconds, repeat the whole thing again. Try to start off with 3 sets of this exercise, and after a week or so (every OTHER day!) try to increase the amount of "sets" you do by 1..
That's one of the more effective exercises for your benefit I know...I have equipment at my gym that works the inner/outer thighs but, if you don't have access to that type of machine, this should do...

It's mostly my quads and muscles in my lower back that are having the issues- my squeeze is not the problem- its sustaining a standing a hold on the horses

Ok..then
If you wish to build quads,and associated leg muscles that hold body weigh in suspension, there are a number of "home" exercises you can do.
1. Try "half squats"..slowly lower your self down bending your knees to half-way (don't go down all the way, not good for the knees), hold, slowly lift up...do this 5-10X, 30 seconds break and repeat. If you can do so, 1 or 2 more sets of the 5-10X repetitions, then give your self a day off, then repeat the exercise. After 1 to 2 weeks add either more repetitions to your routine, or add weight in your arms, even a weight bar, or both. Try 5 or 10 lbs extra at first, and see how it goes.
2. To add strength to your calf muscles (and you likely will need this too) the simplest thing is to stand with your toes+balls of the feet on a stairs, or anything where your heels are well of the ground (brace yourself on the handrails, don't take much weight in your hands)then dip your heels down , and lift yourself up with your calf muscles..do 5 -10 X, and do 2 to 3 sets of these repetitions.
3.If you need more "core" strength,to include the "back-side" then try this..lay flat on the floor face-up, put your legs together and lift up both legs (keep them straight for maximum effect). Only lift them 2-4" off the floor,hold, and you will see how many muscles that will work.
If for any reason you have difficulty lifting both your legs, bend them at the knee, and try that for a while.
There are many many more variations for this, but do those for a few weeks (every other day is best for the exercise to work, and not injure yourself) and you should feel the difference! It can be difficult at first, but it will pay off...good luck and don't forget to stretch! Preferable before and after...these have worked well for me, especially before I found a gym with the right equipment...

Awesome thanks heaps!!!!!!!!!!!

Does anyone know how thi's new technique will affect my other riding?

Anyone experienced this?

It helped my riding tremendously. If you stick with it, you will have strength in your lower back and abdominals that you will not believe possible. It helped me ride with a relaxed, flat back rather than an unnatural hollowed back and it taught me how to take my leg on and off at will. All that work on school horses and work without stirrups as a young rider gave me a vise grip leg.

Getting through the getting fit phase is a bear, but after that it's just pure joy.

Awesome! Thanks