One time this happened, the chain was frozen in the low gears and wouldn't shift onto any of the highest gears. This happened right by a LBS. They popped it up on a workstand and couldn't get it to shift. It only worked if they manually pulled on the cable. They squirted a bunch of lube in the shifter and then told me I would have to leave the bike. Being 15 miles from home, I figured this was a long walk in cleats and opted to ride the damaged bike home. One mile later it unfroze. This hasn't happened since, but the other shifting issues persist.

Thanks for your reply