If you think changing jobs doesn't come without a price, you're very wrong. A better one gives you more obligations and that's ok, if you're ready for it. Most people think of a better job in terms of more money. They don't realize that if they can't do whats required, they will get demoted or even canned. Besides that, they may hate the new position. You know the grass is always greener syndrome. It very much exists in the working world.
When you want to apply for a new position, especially in another field, make sure you can do the job. If you are just hoping to get trained, don't count on it. Companies are lacking in training these days and even if the requirements seem simple, you should talk to someone who knows about the position. This way you will have all the details about it and feel more comfortable.
Find out if the job has a procedure manual as well, if you can. Even if the new position has a procedure manual though, if it's from 1983, it probably won't do you much good. Procedures change over the years, drastically. Depending on what field you work in, it may be an audit requirement to have the procedures updated. If you are applying for a job within your own company, this will be easy enough to do. If not, only if you know someone should you ask.
Sometimes when you apply for a position, the requirements are not quite accurate to the least. It may have more underlying responsibilities not mentioned in the list of duties. This happens all the time. You are being paid less for doing more. You are responsible for much more and left to fend for yourself. There may be a little blurb in the duties to cover what was not mentioned. This is where the headache comes in.
The thing you have to decide the most is: Is the headache of the job worth the money. Is it enough money for all the headaches and extras you have to put up with? Will it lead to a better future in this career? You have to have a good feeling that in the end, it is or will be worth the while somewhere in the future. If not, you are just going on a nowhere road to be unhappy and unfulfilled in the job world.
My advice to you is not that you should never take a chance but to be more prepared, if possible, in the details of the job. This way your decision will be a more educated one and hopefully this will lead you closer to the right job.