Now, did you go to a professional back defucker? Because if you just defucked it on your own, you could end up refucking yourself pretty quickly.
I like the idea of push presses or jerks. It brings everything into the movement. Also, some overhead barbell walks may not be a bad idea. One nice quick movement Dan John has advocated are pressouts, or partial reps at the end of any set of overhead presses.
After every set of presses, keep the bar locked out, then do 6-8 very short R.O.M. presses, like, just 3-4 inches. It'll burn your tris like nothing, but it'll also give your core and base (read - your body from the armpits to the feet) some extra stabilizing work.
Of course, the shivering legs could just be your body telling you that the weight's too heavy, and it doesn't like it very much.