Morning stiffness in fingers and in other joints, is very common for rheumatoid arthritis.
Most commonly, small joints of the hands, feet and cervical spine are affected, but larger joints like the shoulder and knee can also be involved.
Although, joints in RA are affected symmetrically, in the beginning of disease, the large joints can be affected asymmetrically (only one shoulder, one knee).
The symptoms of arthritic shoulder are tenderness around the joint, pain with activities, limited range of motion, swelling and stiffness of the shoulder.
It is very possible that you have neck spine arthritic changes that may lead to pain in your shoulder and arm.
Visit a reumatologist as soon as possible!