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.
The description you provide makes it difficult to localize without the ability to do a formal examination. However I will try to provide you with some useful information.
Pain in the shoulder joint worse with movement may be inflammation of the tendon or joint. The treatment is conservative initially which includes NSAIDs and physical therapy. However, if you have any neurological findings such as weakness, numbness, changed reflexes, etc, you may have a nerve injury. The best way to determine this is a formal evaluation by a neurologist. Nerve injury is initially treated with NSAIDs but if they fail, you may need medications such as gabapentin or pregabalin which are medicines used routinely for neuropathic pain. Additionally, an MRI of your neck may be needed to further evaluate
You should seek medical attention including a complete physical examination. You may need a referral to a neurologist if anything is abnormal or concerning.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.