I couldn't tell you what they mean, if you go on Google you can find a site that will help "interpret" common themes in dreams. If it causes you distress or interrupts your sleep a lot you may want to consider speaking to somebody in a more professional setting. As far as control goes, I believe you can and you can also read up on it using Google, but it seems to be a difficult ability to gain control of, no pun intended.

Personally I don't often recall my dreams, I have a lot of anxiety and panic attacks so I'm not sure how much I actually get to spend in the REM cycle every night. Anyway, do some research, you never know what you'll uncover.