It's so difficult to work out what's going on, isn't it? We just sit there, nodding our heads and it's only when we get out that we think, "Hang on a minute, what did that actually mean??" That's why taking a clever, sensible friend is always a good idea! ;)
I would say that they know you have a cyst but they want to check to see if anything else is going on in there. It's great that they can do the colposcopy tonight. Can you take someone with you? How about writing down some questions and make sure you ask them in the colposcopy clinic. You could ask whether the cyst could be causing your symptoms? What do they want to do about it? What does that involve? During the colposcopy: what can they see? When will you have the results? What will happen at the hysteroscopy clinic? Why do they want to do that?
I'm sure you will have lots of questions of you own, but, seriously, write them down. Once they're shining a light up you and checking your cervix out with a microscope it's likely you'll forget everything! ;)
I hope it goes really well for you!