This sounds like your editing program is using a de-interlacing method called 'blending'. This is where the first and second fields are averaged together. It will cause blurring along vertical edges when the camera pans. Horizontal lines will stay sharp, this is the way to tell.
Another possibility is your editing program is taking short cuts to present the video on your screen in real time in order to keep up while you're viewing it. Takes a lot of processing to handle motion, but very little for static scenes. The final output file may not have this blurring effect since the editor can spend all the time it needs to get it right. Video is horribly demanding of PC resources. The larger the format, the worse it gets. Full size high definition is murder. The big studios use specially designed arrays of high powered PCs to do things in real time without resorting to such tricks.
Fav quote - "Experience is whatcha don't get 'till ya don't need it no more."
System - Athlon 1.4GHz, Win98, Hauppauge PVR250 receiver and compressor.
Software -Magix Movie Edit Pro 10, Nero 6 + NeroVision Express, Moho 4.61, PSP 8.1, Bryce, Quicktime 6.52 pro, Goldwave 5, DVD-Lab.
Cameras - Panasonic GS9, Canon ES8400V, Canon EOS D20 and Canon A70