Trust me, if you have flutter you had better not be putting the plane in the air. Flutter can literally reduce a plane to pieces in a matter of seconds. This is something that you need to have and EXPERIENCED pilot at your field look at. Because it's very hard for us to tell what the problem may be unless you can give us a better description of what's going on. But please don't ignore this situation. As I said, IF it is flutter you should NOT be flying this plane until it's corrected.

Hope this helps

Ken