In the UK you can patent an invention, a process or a formula. Ideas are easy to have - everybody gets ideas, but you can only patent something when you know how it will work. You need to make a working model or a sketch of your idea, then apply for a provisional patent, (cost about 10 years ago was £25). That will protect you for a year in which time you (or a patent agent that you pay) will need to:
1) Check if someone else already has had the idea and either patented it or just marketed it. If so they have what is called prior art and you are screwed.
2) Try and interest a company in manufacturing and/or marketing your idea.
Of course if you are not in the UK the rules may be slightly different, and you will need to take out separate patents for every country in which the item is to be marketed. You could try a European patent for the EU countries but these are very costly and less easy to enforce than having a patent granted in the individual countries.
You need to be able to describe how your idea works. The idea must be original and not obvious. Oddly, the idea does not need to actually work.
It sounds like you have stumbled upon a problem but have yet to devise a solution. You can't patent a problem, only the solution to a problem, so until you have invented it there's not much point worrying about patents.
The first place to start looking is Google to try to find if the problem has been solved already. If yes, unless you can do it better forget about it. Next try searching patent offices - at least to a limited degree, this is now possible online I think. This will give you some idea of what is necessary for a patent.