Hi there,
From my own 'independent research' (so to speak... basically just frantic googling) on ALS, etc I'm fairly certain that the EMG is generally considered the standard test for ALS, so the fact that yours came back clean is a very good sign
As far as the physical symptoms you've been experiencing, they are associated with ALS but are more often caused by conditions that are far less severe- all of them can be caused by anxiety, for instance. Also, as far as I've heard,
ALS sufferers tend to, even in the early stages, have a very sudden onset of symptoms that never improve or subside at all (for instance, they begin to limp in one leg or can no longer button up their shirts, etc).
I also experienced basically all of those symptoms at once and it turned out to be simply the product of my bad posture and time spent hunched over a computer/guitar- is this a possibility for you?
Statically, the chance of someone your age having ALS is something like 1 in 200 million; I don't mean to invalidate your worries at all but keep that statistic in mind, as the odds are in your favour.
I'm not a doctor and your neurologist will obviously know much better than me but I hope my experience helps to ease some of your concerns and that all your tests come back fine.
Take care.