Pain in the shoulder could indicate certain types of cancer, such as osteosarcoma or Ewing's sarcoma, notes Mayo Clinic and the American Academy of Orthopaedic Surgeons. There are, however, many other common causes for shoulder pain.
Osteosarcoma normally presents other symptoms along with pain, such as smaller muscle size in the affected arm, states Healthline.
Rheumatoid or septic arthritis, separated or frozen shoulder, and common sprains or strains may cause shoulder pain, notes the Mayo Clinic. Tendinitis, rotator cuff injury and torn cartilage are other common causes of pain in the shoulder. Sometimes, shoulder pain can indicate serious conditions such as a heart attack or broken arm. Shoulder pain that does not go away is a reason to see a doctor.