The neurologist relies on clinical presentation, blood testing, imaging and EMG. They do not go hunting for a particular disease, they use all forms of testing to eliminate possible diseases and to gain information about possible routes of investigation moving forward. If they can't find anything within their field of expertise, then it is not neurological. If they have ANY doubts, they continue with testing, continue observation or refer you on to the person they think will be able to identify the cause of symptoms.
It is important to understand that neurologists can pick up on even faint symptoms through strength testing, reflexes and observation on how you move, hold yourself and walk. EMGs can sometimes pick up on pathological nerve issues WELL before a patient is even aware of movement issues. If your emg is clear and the neurologist says they can't detect anything based on their in-person tests of your reflexes, strength and movement, there is nothing people here can say to reassure you if you don't believe the neurologist.
I am sorry you are frustrated and anxious about your health. However, there's not much more people here can do for you as it is a support group for people who have been diagnosed with, or are caring for someone with ALS. Work with your family doctor to get to the root of your symptoms and keep an open mind to what may be causing your worries.