worried about als

I have noticed fasciculations and felt them on both feet and legs and doctor reports brisk reflexes I think on both no clonus and no babinski.  

I have had arm achiness in both arms in October.  Now for past 3 weeks I had great pain when I extended my L arm outwards...and a little on right.  I probably guarded the L arm.  I asked physical therapist to look at my arm and she could see atrophy in  L bicep.
Also in the antecubial area when flexed the tendon pops out and there is quite a dent.  

Does atrophy cause this pain when my arm is extended.  Am I looking at ALS.  

the doctor ordered a nerve conduction study