Not pregnant but having movements like baby kicks, what causes that to happen?

Tow possibilities: Other than you imagination, there are two things that might be doing this. The intestines move constantly and sometimes you can be more aware of this. Second, the abdominal wall musculature can have twitches or what are called fasiculations. This is innocent, not serious, but feels quite funny. It is the same as an eye twitch, which you can see. In the abd muscles you will feel, not see these.