the force required to move the freewheel pawls is greater than the bottom bracket bearing drag. if you grab the pedal the freewheel engages and the wheel continues to spin right? if not then you have a track bike.

The only time I've ever had that happen was on my mtb and it turned out to be the parts inside my rear hub had completely broken apart. Hope that's not the case for ya.

Probably just need to have your freehub taken apart, cleaned and lubed.

  If you try to stop the cranks from spinning what happens? If the chain starts hopping and jumping all over the place the freehub is bad. If the wheel "coasts" and you hear the normal clicking sound you are okay and the freehub body needs service.

Thanks. If I try to stop the pedals, it keeps spinning so I guess my freehub needs servicing - I'll be off to the bike store today.