First of all, keep in mind that I am unable to diagnose you because I am unable to examine you, this forum is for educational purposes.
I agree that some information on ALS will be helpful for you. The symptoms that you describe of twitches in the calves in the absence of weakness or atrophy is not consistent with ALS (also called motor neuron disease). The twitches that you describe are likely fasiculations and these can occur in normal people, after exercise, after a viral infection, with electrolyte imbalances, and also in some neuromuscluar diseases including ALS. The vast majority of fasicualtions are benign, and are termed benign fasicualtion syndrome. In ALS fasicualtions accompany weakness and atrophy of muscles. Fasiculations are not an early sign of ALS and without other features, fasiculations themselves should not give concern about ALS. Other 'clues' is that benign fasiculations tend to be more wide spread (all over the body, on both legs, etc.) while in ALS the fasiculations tend to be more prominent in the muscles that are affected by weakness and atrophy as well. In patients that present with isolated fasicualtions, I suggest several things: first an EMG (muscle-nerve test that will show specific changes if there is signs of ALS) to put your mind at ease that in addition to no weakness or atrophy there is also no electrical signs of ALS. Second, an electrolyte panel including sodium, potassium, chloride, Co2, BUN, creatnine, calcium, magnesium and phosphorus (blood work).
I hope this has been helpful.
Please be advised that I am not responding to you as a physician but that of education, and information.
A few variables fit for ALS but it seems that there are not nearly enough. Your family doctor as we both know is not qualified to say "no" but he is qualified to see danger signs. To get this fear out of your mind see a neurologist who specializes in ALS. And, do not forget to do some research on Lyme disease, et al.
Good Luck!
JCmcc.
Good Luck