Shoulder pain can stem from one or more of the following causes: 1  Strains from overexertion. 2  Tendonitis from overuse. 3  Shoulder joint instability. 4  Dislocation. Collar or upper arm bone fractures.  Frozen 1  shoulder. Pinched nerves (also called radiculopathy)
Joint pain can affect one or more joints. Joint pain can be caused by many types of injuries or conditions. It may be linked to arthritis, bursitis, and muscle pain. No matter what causes it, joint pain can be very bothersome. Some things that can cause joint pain are: Autoimmune diseases such as rheumatoid arthritis and lupus.
Pain and stiffness in the muscles and joints can be caused by long-term muscle tension, postural imbalance, overuse and injury. All these things can cause muscle fibres to become shortened, tiny pockets of scar tissue to form (fibrosis), and larger areas of scar tissue will get laid down as an injury heals.