allways havin clutch issues

Hi all like the title says Im allways havin clutch issues, usually the issue is that the clutch works fine at first, then after I ride for a while it wont let me freewheel as well.today it completly "slipped and wont grab at all, I rode home and the nut that holds the gear on(chain side)backed itself off. I put it back on and tight and the clutch still wont grab or start now. my pads look pretty worn could that be it or did I strip something inside mabye? thanks for any help out there

so Ive spent about the whole day tring everything mentioned on this site on clutches and still no grab at all, Im about outta ideas still wont grab at all not even to start so what could this be? help!!!
Ive tried everything I dont wanna give up but im real close to being over this whole thing

I do have alot of miles but the problem was actually the woodriff key in the gear(chain Side) was missing. I replaced the key(I had to use a dremil to get it to fit right) reassembled everything, let out the clutch and vroom vroom it starts and moves again. seems like something that could happen alot being soo much torque on that tiny peice of metal, supprised I couldnt find much on the subject here.
below is the woodriff key for those who dont know what it is. I didnt untill now