Hi. Thank you very much for your question. I am a board certified neurologist in the U.S. I will be happy to help.
If most of the arm is affected with this symptom, then I would agree that a pinched nerve at the level of the neck would be the most likely cause. The neck portion of the spine (called the cervical spine) has nerve roots that come from the spinal cord, and can sometimes be compressed by bony changes or a disk bulge in that area.
Less likely would the tingling and paresthesias be arising from the shoulder region. This can occur, but is much less common. In terms of investigations, an EMG/nerve conduction study would be a reasonable test to evaluate for a problem coming from the cervical spine, and also to rule out other causes such as a nerve compression at the elbow or the wrist (these are termed ulnar neuropathy and carpal tunnel syndrome, respectively).
Depending on the evaluation and examination, a doctor treating you may elect to do an MRI scan of the Cervical Spine to try to visually see whether there are any pinched nerves in the neck. These would be the 2 investigations that could help figure out where your symptoms are coming from.
Hopefully this has been helpful to you. Please let me know if there are more questions. If this has been helpful, please rate me highly. Bonuses always appreciated. Best of luck.