So, I was working on a project that involved rigging, and everything seemed to go fine when I was working with a single bone (extruding it). But then I wanted to use the same sequence of bones to rig the other 2 legs of the model, so I copy-pasted them and put them into place. Since then, It's been impossible to work in that file. When you try to select something, it takes forever, or when you rotate around in the 3d view, Its super laggy. To solve the view lag, I tweaked some stuff, and it seems to go better. But I still have the selecting problem.
Had a similar problem, but not with rigging. Check the size of your .blend file and see if it seems too large for your average model. I once made a simple hanger for clothes and it's size was over 15mb. I deleted few objects and managed to find out what was causing it. If your file seems too large, try deleting the object/bone that makes blender lagspike the most when you select it and save the file somewhere to see if that fixed it.
PS: wanted to comment, but you apparently need 50 points to do that...