What Causes Weakness, Twitching In Right Side Of Body?

Question: Hello, im a 19 year old male. Ive spoke to two neurologists on this website already and I am very happy with their answers however I have a few more concerns. For a few weeks now I've been experiencing weekness throughout my body. I went to my physician and he did a CBC Test and everything came back absolutley perfect. From my cholestorol, to my hemoglobin he said theres nothing i should be concerned about. However I am still concerned about the weekness in my arms when I comb my hair or my legs when I walk. I am not fatique and I do not feel tired. My doctor tells me it can be simple growing pains in my body. About a week ago I noticed twitching in my right arm for a brief second and now twitches throughout my body but they are mild and only last for half a second. I notice more twitching in my body right before I fall asleep in my calfs. I used to be very active and workout a lot so I do not know if this twitching is occuring due to the fact that I am slowly starting to workout again. Last time I worked out my legs 2 days ago I was so out of breath I thought my heart was going to jump out of my mouth. At times I also have dificulties taking deep breathes which makes me have to yawn to catch that full breath. I did some research and I am extremely concerned about this being ALS. I know its uncommon in my age but I am still EXTREMELY stressed about this matter. Also the joints in my fingers bother me but my grip is not weak nor do I trip or lose my balance. I am also perfectly capable of lifting weights and exercising my biceps, chest and triceps. Please advise whether I should be too concerned and whether a trip to a neurologist to get an ECG is necessary. Also please note my hands are very sensitive to the cold weather and are always RED, Cold and sweaty. Im from New York so we've been experiencing some below freezing temperatures here. Please advise. Thank you.