I Have Severe Pain In My Shoulder, Neck, Underarm, Should

I have severe pain in my shoulder, neck, underarm, should blade with radiating pain down my arm with tingling in the fingers and some numbness in my right arm.
When I move my arm, it either worsens or I get temporary relief.
This has been going on for approximately 2 weeks.
What could be wrong?
I wasn't aware of a charge. I have Medicare and Medicare.
I am on a very limited income. If you CAN'T help me, THANK you for your time.
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