The causes for feeling weak all over are diverse: muscle problems (polymyositis, muscle dystrophy,drug induced), thyroiid problems, peripheral nervous system issues (Guillain-Barre),vitamin deficiencies, anemia, depression. People with other symptoms, such as fatigue (tiredness, feeling exhausted), sleepiness, will often say they feel weak and it can be hard to distinguish some of these from actual muscle weakness. Then, the specific treatment depends on the cause. I suggest that you get a comprehensive evaluation by your PCP and once determined the cause proceed with the right treatment option. Regarding the pain in the left hands and fingers it would be important to rule out a peripheral neuropathy and the most common in this category would be a Carpal Tunnel Syndrome.
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