I have similar symptoms due to degenerative disk disease/stenosis @ C6/C7. Twitching is almost always neurogenic & that you have radiant pain in your trap & humorus makes me lean towards a dyskinesia caused by pinching @ the nerve root in the neck. Some gentle stretching might help. You said you're a Marine (Semper Fi), do you have any medical records from your service as a comparison? Also, the VA might be able to help.
Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.
Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.
It must be emphasized that in the majority of cases muscle twitches are benign meaning that they are of no consequence and are not resulting from a serious cause. In such cases, the twitches may be related to anxiety/stress, caffeine, and often occur after recent strenuous activity or muscle over-use. It is important in such cases to reduce stress/anxiety levels and to reduce caffeine intake. Tremors of the hands can be physiological that is exacerbated by stress/anxiety and caffeine.
Benign fasciculation syndrome is a condition in which there are involuntary twitches of several muscle groups, most commonly the legs but also the face, arms, eyes, and tongue. If the diagnosis is confirmed and other causes are excluded, it can be safely said that the likelihood of progression or occurrence of a serious neurologic condition is low. When this condition is present but not particularly bothersome or disabling, treatment is not necessary. If severe and it requires treatment, there are a few medication options though this condition is not very common, and the research that has been done on its treatment is limited. Minimizing caffeine and stress, and treating anxiety if it is present, will improve your symptoms.
\There are other causes of muscle twitches, but they are usually associated with other neurological deficits. This group includes ALS; however, your symptoms based on your description is not consistent.
Another nervous system problem, neuropathy, may also lead to fasciculations. There will again be associated weakness or sensory changes. It would be interested for you to discuss this with the neurologist who did the EMG to see if the “compressed nerve” innervates the area that is twitching (e.g.,ulnar, C8 root, plexus, etc).
Like you mentioned, these symptoms may reflect emotional/psychiatric problems related to stress (what is called somatization disorder). The latter is a true medical condition whereby instead of a patient experiencing depression or anxiety, they experience physical symptoms, and once the stress is addressed, the symptoms resolve.
Lastly, have you had any blood work completed such as CBC, CMP, TSH? Metabolic changes can cause muscle twitching.
I suggest follow up with you follow up with a neurologist. It would be useful to have a thorough examination.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.