Right shoulder pain for months now?

See a physician: Shoulder pain can be caused by multiple different things: rotator cuff tendinitis or tear, arthritis, bursitis, referred pain from your neck, muscle pain in the shoulder girdle, cartilage defects, or even tumors or infections. If you have persistent symptoms, you should see a physician and begin the workup to determine the cause. Treatments will depend on the diagnosis/cause. Good luck!

Get evaluated: Severe shoulder pain could have multiple causes including infection, nerve compression, overuse, tendon tears (rotator cuff), trauma, and even a neoplasm. A physical examination and diagnostic imaging will likely be necessary.

See doctor: and have it checked and diagnosed then it can be treated.