for the last week my right thumb feels week... i play guitar so when i grab a pick it feels like its going to fall out my hand... the rest of my hand feels fine but thumb just has this week feeling... i lifted a chair with my thumb so im confused as hell.. is this how something like als begings or is it more of the whole hand/?.. and im i worrying for nothing.. right now im scared to death.. 49 year old male thanks everyone for your advice