Okay based on these additional info I feel you may be suffering from a condition called as TOS.
TOS (thoracic outlet syndrome) is a condition where compression of the nerves supplying the upper limb takes place at an area called thoracic outlet. This area corresponds roughly to the upper chest, lower neck & the shoulder areas. This is an area where compression of the nerves supplying the upper limb may take place and this condition will present with pain in the shoulder/shoulder blade area that radiates down the arm to the hand & fingers. Neck movements too can trigger or worsen these symptoms. Since you mentioned bending the neck seems to precipitate or worsen your symptoms so I am suspecting TOS possibility too (especially considering you are not having much neck pain too). The nerves in the thoracic outlet area get compressed by structural problems like a ligament band, an extra rib called cervical rib, thickened muscle or other soft tissues in that area causing the compression & the symptoms.
You need investigations including an MRI specially to look at Thoracic outlet area and an EMG/Nerve conduction study (a nerve & muscle test) to confirm the diagnosis. The EMG test can look for TOS, pinched spinal nerve & CTS etc (one test that looks for all possibilities) and the MRI of the thoracic outlet will show whether there is any structural pathologies in that area causing the TOS (if you indeed have this condition).
Once a final diagnosis is made appropriate treatment will be started. If you indeed have TOS then depending upon the mri result you may need a decompression surgery (to decompress the compressed nerves). If you have pinched spinal nerves based on emg test then ESI can help (even if neck pain absent). If CTS is too present it will be treated appropriately (CTS brace or splint using etc). For the pain and other symptoms you may also use nerve-pain pills like Gabapentin or Amitriptyline. A muscle relaxant like Baclofen or Tizanidine too may help for symptoms like soreness.
You may please discuss all these above points with your clinic-drs, preferably with a neurologist for the further needful (clinical evaluation/examination, investigations like MRI of thoracic outlet area and EMG test etc) and once a final diagnosis is made it will be treated appropriately including the above mentioned symptomatic treatments.
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