Hi, Thank you for your question. This muscle twitching is also called as muscle fasciculation & appears when the muscle contracts on its own (without nerve stimulation). Most of the times these symptoms occur without any underlying disorder & they are not harmful or may appear after anxiety, hormonal imbalance, viral illness or long term illness. But sometimes this muscle twitching appears as atrophy and weakness of muscle as well. Most likely cause of this twitching with weakness or atrophy of muscle can be when the nerve supplying to muscles is not functioning properly due to any neurological disorder. If you suffer continuous weakness and notice reduced strength of muscle bulk in areas, please arrange an appointment with a neurologist right away who will evaluate the possibilities here. Hope this information proves helpful to you. Take Care & Regards!!!
When did this start happening? Does it happen throughout the day or at intervals? Are the motions continuous or tic like in how they occur? It would be worthwhile to see a neurologist who is a movement disorders specialist but also note all this down for them, what previous medications you have taken of any kind, what other conditions you may have had throughout your life, if there is a family history of any neurological disabilities or any other conditions and any other questions they might ask you. They would have to take this into further consideration and do specific tests before they could make a determination within their clinical discretion.