It sounds like you might have a condition known as adhesive capsulitis — a problem of chronic inflammation of the shoulder joint capsule. The shoulder capsule is a covering of connective tissue interconnected with shoulder ligaments and tendons. They all help hold the head of the humerus (upper arm bone) in the shoulder socket.
The inflammatory process causes the capsule to thicken and tighten to the point that the extra fold of capsular tissue needed for full motion overhead gets stuck to itself. There is a loss of normal synovial fluid in the joint.
When this happens, the shoulder can no longer slide and glide smoothly through its full range-of-motion. The capsule loses its ability to stretch. The result is the shoulder gets stuck and becomes stiff and painful. In chronic cases, inflammation is gone but it was the first step that got the process started. Treatment is still directed at the joint capsule.
Hyaluronic acid is a normal part of the matrix that makes up cartilage. It has two distinct properties that make it so important for smooth joint motion. It is both viscous (slippery) and elastic. The viscosity allows the tissue to release and spread out energy. The elasticity allows for temporary energy storage. Together, these two properties protect the joint, help provide joint gliding action (especially during slow movement), and act as a shock absorber during faster movements.
Some experts think hyaluronic acid (HA) injected into the shoulder has some additional benefits. They suggest that the HA reduces inflammation of the synovium (lubricating fluid inside the joint). It also has a direct effect on the pressure inside the joint. Hyaluronic acid may be protective of the joint cartilage and prevent the formation of adhesions that keep the capsule from the smooth gliding action needed for normal shoulder motion.
The use of hyaluronic acid injections into the shoulder has been quite successful for the knee and has just recently been tried with shoulder problems. Studies are beginning to be published with results using this treatment for arthritis, shoulder pain, and adhesive capsulitis. Ask your doctor about the use of this treatment tool for your problem. You may be a perfect candidate or there may be some reasons why a different approach would be better for you.