first off let me start by saying how sorry i am that you're going through this.
now, i too have almost the exact same symptoms, all started in one day for me though course was in reverse..started in my neck where it felt very tight and hard to turn, even have some jerks in it, then my arms and legs at the same time eem to shake when i lift the against gravity, it doesnt happen un less im using the muscles. went to neuro, said its not ALS, MS, things of that nature...but like you i worry..also, the little muscle spasms all over the body, i have those also..have they checked your b12, vit d, magnesium?? i was found to be extremely low on all of these..endo disorders are also something that should be looked at. i found out through going to the dr for the problems i listed that i have hashimotos disease as well. i know its hard not to think the worst, but its very unlikely that either of us has ALS. just one thing off in your body can cause a whole host of problems. make your dr test all things, be persistant, thats what im doing, pressing them to help me. its so frustrating to have a dr say "well, you look great" so what, im sick, something is veru wrong..and they so easily dismiss things that they can not see. if you would ever like to talk im all ears. best of luck and health to you :)
First I'm no doctor but --
Your doctor has done tests, and he said that it's not ALS. You can always get a second opinion, but based on your symptoms I would agree from what I've read over the last few weeks. That it is not ALS.