How far if any are you lowered? Sounds like you may be rubbing on the wheel arch.. easy way to find out is to rub your finger in the arch near the wheel... On a coupe it sounds like a bag of spanners in the boot! If you not lowered and you are rubbing you may have other issues... If its not lowered and your not rubbing then you need to get it looked at... if it is an ARB then it could be loose and if it drops just on one side then you may have a big issue!! Best to get it looked at!
To the OP! Could be a few things but it shouldnt be happening! Take the door card off! Dead easy, pop the little cover in the door handle pull bit, one screw in there, remove the cover with the window control, upplug the wires underneath, 2 more screws in the door panel, remove, then from the bottom get your fingers under the door and pull up, the door card hooks on to the top of the door. little panel with the tweeter speaker in could come off but may just stay, either way no bother! so with door card off just check all the screws inc the speaker as this may have worked free.... It also may be door lock! 2 bolts in the back of the door, one in the side (of the drivers door.) Pull the lock out slightly and this should expose the door lock (its the brass bit at the bottom) and then make sure the bolt is tight! Also there is a plastic sleave that fits on the bottom of the window that can come loose just fit it back on the bottom of the window...
Should be somewhere in there! Sorry if this was answered in other posts after post 4 but I started writting this and then went away!